Stem cell derived pancreatic islet differentiation

Abstract

Disclosed herein are compositions and methods related to differentiation of stem cells into pancreatic islet cells. In some aspects, the methods provided herein relate to generation of pancreatic ß cell, α cell, δ cells, and EC cells in vitro. In some aspects, the disclosure provides pharmaceutical compositions including the cells generated according to the methods disclosed herein, as well as methods of treatment making use thereof.

Description

RELATED APPLICATIONS This application claims the benefit under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 63 / 274,402, filed on November 1, 2021, entitled “STEM CELL DERIVED PANCREATIC ISLET DIFFERENTIATION,” and U.S. Provisional Application No. 63 / 274,391, filed on November 1, 2021, entitled “ENHANCED DIFFERENTIATION OF PANCREATIC ISLET CELLS,” the entire contents of each of which are incorporated herein by reference. REFERENCE TO AN ELECTRONIC SEQUENCE LISTING The contents of the electronic sequence listing (V013870082WO00-SEQ-ZJG.xml; Size: 40,337 bytes; and Date of Creation: October 27, 2022) is herein incorporated by reference in its entirety. BACKGROUND Transplantation of pancreas or pancreatic islets has been used for treating diabetes, such as type I diabetes. Pancreatic islet transplantation does not need major surgery and the function of the islet grafts can be maintained for years in a recipient. However, a shortage of pancreatic islets donors prevents this therapy from being effectively implemented. Artificial pancreas or pancreatic islets provide an alternative source of transplantable islets. Thus, there is a need for methods of in vitro restitution of pancreatic islets whose function and characteristics resemble endogenous pancreatic islets. INCORPORATION BY REFERENCE All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. Absent any indication otherwise, publications, patents, and patent applications mentioned in this specification are incorporated herein by reference in their entireties. SUMMARY Provided herein, in some aspects, are compositions and methods for producing pancreatic islet cells (e.g., stem cell-derived pancreatic islet cells). In some embodiments, a method described herein comprises contacting pancreatic progenitor cells (e.g., pancreatic progenitor cells that are PDXl-positive and NKX6.1-negative) with a medium comprising a Forkhead Box 01 (FoxOl) inhibitor and a notch signaling pathway inhibitor, and optionally a notch signaling pathway inhibitor. In some embodiments, a method described herein comprises contacting pancreatic progenitor cells (e.g., pancreatic progenitor cells that are PDXl-positive and NKX6.1-positive) with a medium comprising a Wnt signaling pathway inhibitor and a PKC activator. In some embodiments, a method described herein comprises contacting pancreatic progenitor cells (e.g., pancreatic progenitor cells that are PDXl-positive and NKX6.1-negative) with a medium comprising a Forkhead Box 01 (FoxOl) inhibitor and a notch signaling pathway inhibitor, and contacting resulting cells with a medium comprising a comprising a Wnt signaling pathway inhibitor and a PKC activator. In some aspects, a population of in vitro differentiated cells (e.g., stem cell-derived pancreatic islet cells) produced using the compositions and methods described herein are also provided. In some embodiments, the population of in vitro differentiated cells (e.g., stem cell-derived pancreatic islet cells) comprises NKX6.1-positive, ISLl-positive cells and NKX6.1-negative, ISLl-positive cells. In some embodiments, the population comprises more NKX6.1-positive, ISLl-positive cells than NKX6.1-negative, ISL-positive cells. In some embodiments, at least 15% of the cells in the population are NKX6.1-negative, ISL-positive cells; and wherein less than 12% of the cells in the population are NKX6.1-negative, ISLL negative cells. In some aspects, methods of using the population of in vitro differentiated cells (e.g., stem cell-derived pancreatic islet cells) described herein to treat diseases (e.g., diabetes) are provided. Some aspects of the present disclosure provide in vitro compositions comprising a population of pancreatic progenitor cells and a medium comprising a Forkhead Box 01 (FoxOl) inhibitor and a notch signaling pathway inhibitor, wherein the population of pancreatic progenitor cells comprises cells that are PDXl-positive and NKX6.1-negative and cells that are PDXl-positive and NKX6.1-positive. In some embodiments, the medium further comprises a PKC activator. In some embodiments, the notch signaling pathway inhibitor is a y-secretase inhibitor. In some embodiments, the y-secretase inhibitor is XXI, DAPT or derivatives thereof. In some embodiments, the y-secretase inhibitor is XXI. In some embodiments, the FOXO1 inhibitor is of formula (LB): or a pharmaceutically acceptable salt, solvate, hydrate, polymorph, co-crystal, tautomer, stereoisomer, isotopically labeled derivative, prodrug, composition, or mixture thereof. In some embodiments, the FoxOl inhibitor is present in the medium at a concentration of 0.1-10 pM. In some embodiments, the FoxOl inhibitor is present in the medium at a concentration of 1 pM. In some embodiments, the PKC activator is phorbol 12,13-dibutyrate (PdBU), TPB, phorbol 12-myristate 13-acetate, bryostatin 1, or derivatives thereof. In some embodiments, the PKC activator is PdBU. In some embodiments, the medium further comprises one or more agents selected from: a fibroblast growth factor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, and a TGF-P ligand, optionally wherein the medium further comprises a fibroblast growth factor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, and a TGF-P ligand. In some embodiments, the medium further comprises keratinocyte growth factor (KGF), SANT-1, RA, triazovivin, and activin A. In some embodiments, the medium further comprises a water-soluble synthetic polymer. In some embodiments, the water-soluble synthetic polymer is polyvinyl alcohol, poloxamer, polyvinylpyrrolidone, polyethylene glycol (PEG), PEG copolymers, poly(N-isopropylacrylamide), or polyacrylamide. In some embodiments, the water-soluble synthetic polymer is polyvinyl alcohol (PVA). In some embodiments, the water-soluble synthetic polymer has a concentration of 0.005% to 0.5% (w / v), 0.01% to 0.2% (w / v), 0.02% to 0.1% (w / v), or 0.03% to 0.08% (w / v) of the medium. In some embodiments, the PVA is at most 85% hydrolyzed. In some embodiments, the PVA is about 80% hydrolyzed. In some embodiments, at least 50% of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-negative, and / or no more than 50% of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-positive. In some embodiments, no more than 50% of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-negative, and / or at least 50% of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-positive. In some embodiments, medium does not comprise a Wnt inhibitor. Other aspects of the present disclosure provide in vitro compositions comprising a population of pancreatic progenitor cells comprising cells that are PDXl-positive, NKX6.1-positive, and insulin-negative; and a medium comprising a protein kinase C (PKC) activator and a Wnt signaling pathway inhibitor, wherein the medium does not comprise a FOXO1 inhibitor, and wherein the population of pancreatic progenitor cells had been previously cultured in a medium comprising a FOXO1 inhibitor. In some embodiments, the PKC activator is phorbol 12,13-dibutyrate (PdBU), phorbol 12-myristate 13-acetate, bryostatin 1, or derivatives thereof. In some embodiments, the PKC activator is PdBU. In some embodiments, the Wnt signaling pathway inhibitor is a tankyrase inhibitor. In some embodiments, the tankyrase inhibitor is NVP-TNKS656. In some embodiments, the medium further comprises one or more agents selected from: a sonic hedgehog (SHH) signaling pathway inhibitor, an epidermal growth factor, a notch signaling pathway inhibitor, a TGFP-R1 kinase inhibitor, a thyroid hormone, a bone morphogenetic (BMP) signaling pathway inhibitor, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a histone methyltransferase EZH2 inhibitor, and retinoic acid. In some embodiments, the medium further comprises a sonic hedgehog (SHH) signaling pathway inhibitor, an epidermal growth factor, a notch signaling pathway inhibitor, a TGFP-R1 kinase inhibitor, a thyroid hormone, a bone morphogenetic (BMP) signaling pathway inhibitor, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a histone methyltransferase EZH2 inhibitor, and retinoic acid. In some embodiments, the medium further comprises SANT-1, betacellulin, XXI, Alk5i, GC-1, LDN-193189, thiazovivin, staurosporine, DZNEP, and retinoic acid. In some embodiments, the medium further comprises one or more agents selected from an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, and a one carbon metabolism pathway intermediate. In some embodiments, the medium further comprises an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, and a one carbon metabolism pathway intermediate. In some embodiments, the medium further comprises acetate, P-hydroxybutyrate, taurine, and formate. In some embodiments, the medium further comprises a vitamin. In some embodiments, the vitamin is biotin. In some embodiments, the medium further comprises glutamine. In some embodiments, the medium comprises PDBU, NVP-TNKS656, SANT-1, betacellulin, XXI, Alk5i, GC-1, LDN-193189, thiazovivin, staurosporine, DZNEP, retinoic acid, acetate, P-hydroxybutyrate, taurine, formate, biotin, and glutamine. In some embodiments, the medium further comprises a water-soluble synthetic polymer. In some embodiments, the water-soluble synthetic polymer is polyvinyl alcohol, poloxamer, polyvinylpyrrolidone, polyethylene glycol (PEG), PEG copolymers, poly(N-isopropylacrylamide), or polyacrylamide. In some embodiments, the water-soluble synthetic polymer is polyvinyl alcohol (PVA). In some embodiments, the water-soluble synthetic polymer has a concentration of 0.005% to 0.5% (w / v), 0.01% to 0.2% (w / v), 0.02% to 0.1% (w / v), or 0.03% to 0.08% (w / v) of the medium. In some embodiments, the PVA is at most 90% hydrolyzed. In some embodiments, the PVA is about 87%-89% hydrolyzed. In some embodiments, at least 50% of the population of pancreatic progenitor cells are PDX1-positive, NKX6.1-positive, and insulin-negative. In some embodiments, the in vitro composition further comprises = pancreatic endocrine cells that are PDX1-positive, NKX6.1-positive, and insulin-positive. In some embodiments, the Wnt signaling pathway inhibitor is present in the medium at a concentration of 0.2 pM-2 pM. In some embodiments, the Wnt signaling pathway inhibitor is present in the medium at a concentration of about 2 pM. Further provided herein are methods comprising culturing a first population of cells in a first medium, wherein the first population of cells comprises pancreatic progenitor cells that are PDXl-positive and NKX6.1 negative, and pancreatic progenitor cells that are PDXl-positive and NKX6.1 positive; and the first medium comprises a Forkhead Box 01 (FoxOl) inhibitor and a notch signaling pathway inhibitor. In some embodiments, the first medium further comprises a PKC activator. In some embodiments, the notch signaling pathway inhibitor is a y-secretase inhibitor. In some embodiments, the y-secretase inhibitor is XXI, DAPT or derivatives thereof. In some embodiments, the y-secretase inhibitor is XXI. In some embodiments, the FoxOl inhibitor is of formula (I-B): or a pharmaceutically acceptable salt, solvate, hydrate, polymorph, co-crystal, tautomer, stereoisomer, isotopically labeled derivative, prodrug, composition, or mixture thereof. In some embodiments, the FoxOl inhibitor is present in the first medium at a concentration of 0.1-10 pM. In some embodiments, the FoxOl inhibitor is present in the first medium at a concentration of 1 pM. In some embodiments, the PKC activator is phorbol 12,13-dibutyrate (PdBU), TPB, phorbol 12-myristate 13-acetate, bryostatin 1, or derivatives thereof. In some embodiments, the PKC activator is PdBU. In some embodiments, the first medium further comprises one or more agents selected from: a fibroblast growth factor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, and a TGF-P ligand. In some embodiments, the first medium further comprises a fibroblast growth factor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, and a TGF-P ligand. In some embodiments, rein the first medium further comprises keratinocyte growth factor (KGF), SANT-1, RA, triazovivin, and activin A. In some embodiments, the first medium does not comprise a Wnt signaling pathway inhibitor. In some embodiments, the first medium further comprises a water soluble synthetic polymer. In some embodiments, the water-soluble synthetic polymer is PVA, further optionally wherein the PVA is at most 85% hydrolyzed (e.g., 80% hydrolyzed). In some embodiments, the first population of cells are cultured in the first medium for about 20-80, 20-60, 20-50, 30-50, 30-55, 24-72 hours, resulting in a second population of cells. In some embodiments, the first population of cells are cultured in the first medium for a period of 24-48 hours, resulting in a second population of cells. In some embodiments, the method further comprises culturing the second population of cells with a second medium comprising a Wnt signaling pathway inhibitor and a PKC activator. In some embodiments, the Wnt signaling pathway inhibitor is a tankyrase inhibitor. In some embodiments, the tankyrase inhibitor is NVP-TNKS656. In some embodiments, the PKC activator is phorbol 12,13-dibutyrate (PdBU), TPB, phorbol 12-myristate 13-acetate, bryostatin 1, or derivatives thereof. In some embodiments, the PKC activator is PdBU. In some embodiments, the second medium further comprises one or more agents selected from: an epidermal growth factor, a thyroid hormone, a TGFP-R1 kinase inhibitor, a notch signaling pathway inhibitor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a bone morphogenetic (BMP) signaling pathway inhibitor, and a histone methyltransferase EZH2 inhibitor. In some embodiments, the second medium further comprises an epidermal growth factor, a thyroid hormone, a TGFP-R1 kinase inhibitor, a notch signaling pathway inhibitor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a bone morphogenetic (BMP) signaling pathway inhibitor, and a histone methyltransferase EZH2 inhibitor. In some embodiments, the second medium further comprises SANT-1, betacellulin, XXI, Alk5i, GC-1, LDN-193189, thiazovivin, staurosporine, DZNEP, and retinoic acid. In some embodiments, the second medium further comprises one or more agents selected from an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, and a one carbon metabolism pathway intermediate. In some embodiments, the second medium further comprises an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, and a one carbon metabolism pathway intermediate. In some embodiments, the second medium further comprises acetate, P-hydroxybutyrate, taurine, and formate. In some embodiments, the second medium further comprises a vitamin. In some embodiments, the vitamin is biotin. In some embodiments, wherein the second medium further comprises glutamine. In some embodiments, the second medium comprises: PDBU, NVP-TNKS656, SANT-1, betacellulin, XXI, Alk5i, GC-1, LDN-193189, thiazovivin, staurosporine, DZNEP, retinoic acid, acetate, P-hydroxybutyrate, taurine, formate, biotin, and glutamine. In some embodiments, the second medium does not comprise a FOXO1 inhibitor. In some embodiments, wherein the second medium further comprises a watersoluble synthetic polymer. In some embodiments, the water-soluble synthetic polymer is polyvinyl alcohol, poloxamer, polyvinylpyrrolidone, polyethylene glycol (PEG), PEG copolymers, poly(N-isopropylacrylamide), or polyacrylamide. In some embodiments, wherein the water-soluble synthetic polymer is polyvinyl alcohol (PVA). In some embodiments, the water-soluble synthetic polymer has a concentration of 0.005% to 0.5% (w / v), 0.01% to 0.2% (w / v), 0.02% to 0.1% (w / v), or 0.03% to 0.08% (w / v) of the medium. In some embodiments, the PVA is at most 90% hydrolyzed, optionally wherein the PVA is about 87%-89% hydrolyzed. In some embodiments, the Wnt signaling pathway inhibitor is present in the second medium at a concentration of 0.2 pM -2 p M. In some embodiments, the Wnt signaling pathway inhibitor is present in the second medium at a concentration of about 2 pM. In some embodiments, the second population of cells are cultured in the second medium for about 20-80, 20-60, 20-50, SOSO, 30-55, 40-120, 40-100, 60-110, 70-110, 80-110, 80-100, 90-100, or 24-72 hours, resulting in a third population of cells. In some embodiments, the second population of cells are cultured in the second medium for about 24-72 hours, resulting in a third population of cells. In some embodiments, the second population of cells are cultured in the second medium for about 72-120 hours, resulting in a third population of cells. In some embodiments, the method further comprises culturing the third population of cells in a third medium comprising: a thyroid hormone, a TGFP-R1 kinase inhibitor, a notch signaling pathway inhibitor a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a bone morphogenetic (BMP) signaling pathway inhibitor, a histone methyltransferase EZH2 inhibitor, an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, a one carbon metabolism pathway intermediate, a vitamin, glutamine, and a water-soluble synthetic polymer. In some embodiments, the third medium comprises GC-1, ALK5i II, XXI, triazovivin, staurosporine (SSP), LDN193189, DZNep, acetate, P-hydroxybutyrate, taurine, formate, biotin, glutamine, and PVA, optionally wherein the PVA is at most 90% hydrolyzed. In some embodiments, the third population of cells are cultured in the third medium for about 20-80, 20-60, 20-50, 30-50, 30-55, 40-120, 40-100, 60-110, 70110, 80-110, 90-110, 70-120, 80-100, 90-100, or 24-72 hours, resulting in a fourth population of cells. In some embodiments, the third population of cells are cultured in the third medium for about 48-96 hours, resulting in a fourth population of cells. In some embodiments, the method further comprises culturing the fourth population of cells in a fourth medium comprising a TGFP-R1 kinase inhibitor, a thyroid hormone, a bone morphogenetic (BMP) signaling pathway inhibitor, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a histone methyltransferase EZH2 inhibitor, an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, an one carbon metabolism pathway intermediate, a vitamin, glutamine, glutamate, carnitine, albumin, and ZnSO4. In some embodiments, the fourth medium comprises ALK5i, GC-1, LDN-193189, thiazovivin, staurosporine (SSP), DZBEP, acetate, P-hydroxybutyrate, taurine, formate, biotin, glutamine, glutamate, carnitine, HSA, and ZnSO4. In some embodiments, the fourth population of cells are cultured in the fourth medium for about 20-80, 20-60, 20-50, 30-50, 30- 55, 40-120, 40-100, 60-110, 70-110, 80-110, 90-110, 70-120, 80-100, 90-100, or 24-72 hours, resulting in a fifth population of cells. In some embodiments, the fourth population of cells are cultured in the fourth medium for about 48-96 hours, resulting in a fifth population of cells. In some embodiments, the method further comprises culturing the fifth population of cells in a fifth medium comprising glutamine, HSA and ZnSO4, optionally wherein the fifth medium further comprises acetate, P-hydroxybutyrate, taurine, formate, biotin, glutamate, and carnitine. In some embodiments, the fifth population of cells are culture in the fifth medium for at least 72 hours, resulting in a sixth population of cells. In some embodiments, at least 15% of the cells of the sixth population of cells are NKX6.1-negative, IS LI-positive; and wherein less than 12% of the fifth population of cells are NKX6.1-negative, ISLl-negative. Further provided herein are methods comprising: (i) culturing a first population of cells in a first medium to obtain a second population of cells, wherein the first population of cells comprises pancreatic progenitor cells that are PDX1-positive and NKX6.1 negative, and pancreatic progenitor cells that are PDXl-positive and NKX6.1 positive; and the first medium comprises: a FoxOl inhibitor, a notch signaling pathway inhibitor, a PKC activator, a fibroblast growth factor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a TGF-P ligand, and a water-soluble synthetic polymer; (ii) culturing the second population of cells obtained in (i) with a second medium to obtain a third population of cells, wherein the second medium comprises: a Wnt signaling pathway inhibitor, a PKC activator, an epidermal growth factor, a thyroid hormone, a TGFP-R1 kinase inhibitor, a notch signaling pathway inhibitor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a bone morphogenetic (BMP) signaling pathway inhibitor, a histone methyltransferase EZH2 inhibitor, an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, a one carbon metabolism pathway intermediate, a vitamin, glutamine and a water soluble synthetic polymer (e.g., PVA), and wherein the second medium does not comprise a FOXO1 inhibitor; (iii) culturing the third population of cells obtained in (ii) with a third medium to obtain a fourth population of cells, wherein the third medium comprises: a notch signaling pathway inhibitor, a TGFP-R1 kinase inhibitor, a thyroid hormone, a bone morphogenetic (BMP) signaling pathway, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, and a histone methyltransferase EZH2 inhibitor, an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, an one carbon metabolism pathway intermediate, a vitamin, glutamine and a water soluble synthetic polymer, and wherein the third medium does not comprise a Wnt signaling pathway inhibitor and a PKC activator; (iv) culturing the fourth population of cells obtained in (iii) with a fourth medium to obtain a fifth population of cells, wherein the fourth medium comprises a TGFP-R1 kinase inhibitor, a thyroid hormone, a bone morphogenetic (BMP) signaling pathway inhibitor, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a histone methyltransferase EZH2 inhibitor, an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, an one carbon metabolism pathway intermediate, a vitamin, glutamine, glutamate, carnitine, albumin, and ZnSO4, and wherein the fourth medium does not comprise a Wnt signaling pathway inhibitor and a PKC activator; and (v) culturing the fifth population of cells obtained in (iv) with a fifth medium to obtain a sixth population of cells, wherein the fifth medium comprises albumin and ZnSO4. In some embodiments, the first population of cells are obtained by differentiation of human embryonic stem cells. Other aspects of the present disclosure provide population of in vitro differentiated cells comprising NKX6.1-positive, ISLl-positive cells and NKX6.1-negative, ISLl-positive cells; ISLl-positive cells; wherein at least 15% of the cells in the population are NKX6.1-negative, ISLl-positive cells; and wherein less than 12% of the cells in the population are NKX6.1-negative, ISLl-negative cells. In some embodiments, the population of in vitro differentiated cells comprises at least 60%, at least 70%, at least 75%, at least 80%, about 50-90%, or about 7085% ISLl-positive cells. In some embodiments, at least 20% of the ISLl-positive cells are NKX6.1-negative. In some embodiments, at least 25%, at least 30%, at least 40%, about 30-50%, or about 40-50% of the ISLl-positive cells are NKX6.1-negative. In some embodiments, the population of in vitro differentiated cells comprises up to 20%, up to 30%, up to 40% or up to 50% of NK6.1-positive, ISLl-positive cells. In some embodiments, the population of in vitro differentiated cells comprises less than 25% or less than 20% of NKX6.1-positive, ISLl-negative cells. In some embodiments, the population of in vitro differentiated cells comprises less than 10% or less than 5% of NKX6.1-negative, ISLl-negative cells. In some embodiments, the C-peptide content per 1,000 of the in vitro differentiated cells is at least 300 pM, optionally wherein the C-peptide content per 1,000 of the in vitro differentiated cells is at least 400 pM. In some embodiments, the glucagon content per 1,000 of the in vitro differentiated cells is at least 100 pM. In some embodiments, the glucagon content per 1,000 of the in vitro differentiated cells is at least 200 pM, at least 300 pM, at least 500 pM, at least 600 pM, at least 700 pM, or at least 800 pM. In some embodiments, at least 10% of the in vitro differentiated cells are stem cell-derived alpha cells. In some embodiments, at least 20%, at least 25%, at least 30%, at least 35%, about 20-40%, or about 30-40% of the in vitro differentiated cells are stem cell-derived alpha cells. In some embodiments, at least 35% of the in vitro differentiated cells are stem cell-derived beta cells / In some embodiments, at least 40%, at least 45%, or about 35-50% of the in vitro differentiated cells are stem cell-derived beta cells. In some embodiments, at least 5% of the in vitro differentiated cells are stem cell-derived delta cells. In some embodiments, about 5-10% of the in vitro differentiated cells are stem cell derived delta cells. In some embodiments, at least 5% of the in vitro differentiated cells are glucagonpositive and somatostatin-negative. In some embodiments, at least 5% of the in vitro differentiated cells are glucagon-negative and somatostatin-positive. In some embodiments, less than 10% of the in vitro differentiated cells are both ISL1-1 negative and NKX6.1-negative. In some embodiments, about 5-10% of the in vitro differentiated cells are both ISL1-1 negative and NKX6.1-negative. In some embodiments, less than 20% of the in vitro differentiated cells are both ISLl-negative and NKX6.1-positive. In some embodiments, about 10-20% of the in vitro differentiated cells are both ISLl-negative and NKX6.1-positive. Further provided herein are populations of in vitro differentiated cells comprising NKX6.1-positive, ISLl-positive cells and NKX6.1-negative, ISLl-positive cells; wherein at least 15% of the cells in the population are NKX6.1-positive, ISLl-positive cells; wherein at least 10% of the cells in the population are NKX6.1-negative, ISLl-positive cells; and wherein less than 12% of the cells in the population are NKX6.1-negative, ISLl-negative cells. Further provided herein are populations of in vitro differentiated cells comprising NKX6.1-positive, ISLl-positive cells and NKX6.1-negative, ISLl-positive cells; wherein at least 15% of the cells in the population are NKX6.1-positive, ISLl-positive cells; wherein at least 10% of the cells in the population are NKX6.1-negative, ISLl-positive cells; and wherein between 5-25% of the cells in the population are NKX6.1-positive, ISLl-negative cells. In some embodiments, at least 30% of the cells in the population are NKX6.1-positive, ISLl-positive cells. In some embodiments, 30-60% of the cells in the population are NKX6.1-positive, ISLl-positive cells. In some embodiments, 35-50% of the cells in the population are NKX6.1-positive, ISLl-positive cells. In some embodiments, at least 25% of the cells in the population are NKX6.1-negative, ISLl-positive cells. In some embodiments, 25-50% of the cells in the population are NKX6.1-negative, ISLl-positive cells. In some embodiments, 30-45% of the cells in the population are NKX6.1-negative, ISLl-positive cells. In some embodiments, 1-12% of the cells in the population are NKX6.1-negative, ISLl-negative cells. In some embodiments, 2-12% of the cells in the population are NKX6.1-negative, ISLl-negative cells. In some embodiments, between 5-25% of the cells in the population are NKX6.1-positive, ISLl-negative cells. In some embodiments, between 9-25% of the cells in the population are NKX6.1-positive, ISLl-negative cells. In some embodiments, there are more NKX6.1-positive, ISLl-positive cells than NKX6.1-negative, ISLl-positive cells in the population. In some embodiments, the population of in vitro differentiated cells further comprises a medium. In some embodiments, the medium comprises a sugar. In some embodiments, the sugar is sucrose or glucose. In some embodiments, the medium comprises the sugar at a concentration of between about 0.05% and about 1.5%. In some embodiments, the medium is a CMRL medium or wherein the medium is HypoThermosol® FRS Preservation Media. In some embodiments, the population of cells are in a cell cluster. In some embodiments, wherein the cell cluster is between 125-225 microns, 130-160, 170-225, 140-200, 140-170, 160220, 170-215, and 170-200 microns in diameter. In some embodiments, the population comprises one or more NKX6.1-positive, ISLl-positive cells that express CHGA, MAFB, and / or ESRRG at a higher level (e.g., at least 10%, 30%, 50%, 70%, 100%, 125%, 150%, or 200% higher) than a NKX6.1-positive, ISLl-positive cell from the pancreas of a healthy control adult subject. In some embodiments, at least 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or 100% of the NKX6.1-positive, ISLl-positive cells in a population of cells express CHGA, MAFB, and / or ESRRG at a higher level than at least 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or 100% of the NKX6.1-positive, ISLl-positive cells from the pancreas of a healthy control adult subject. In some embodiments, the population comprises one or more NKX6.1-positive, ISLl-positive cells that express SIX3, MAFA, CHGB, RBP4 and / or FXYD2 at a lower level (e.g., at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100% lower) than a NKX6.1-positive, ISLl-positive cell from the pancreas of a healthy control adult subject. In some embodiments, at least 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or 100% of the NKX6.1-positive, ISLl-positive cells in a population of cells express SIX3, MAFA, CHGB, RBP4 and / or FXYD2 at a lower level than at least 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or 100% of the NKX6.1-positive, ISLl-positive cells from the pancreas of a healthy control adult subject. In some embodiments, the population comprises NKX6.1-positive, ISLl-positive cells that express lower levels of MAFA than NKX6.1-positive, ISLl-positive cells from the pancreas of a healthy control adult subject. In some embodiments, the population comprises NKX6.1-positive, ISLl-positive cells that express lower levels of SIX3 than NKX6.1-positive, ISLl-positive cells from the pancreas of a healthy control adult subject. In some embodiments, the population comprises NKX6.1-positive, ISLl-positive cells that express lower levels of CHGB than NKX6.1-positive, ISLl-positive cells from the pancreas of a healthy control adult subject. In some embodiments, the population comprises NKX6.1-positive, ISLL positive cells that express lower levels of RBP4 than NKX6.1-positive, ISLl-positive cells from the pancreas of a healthy control adult subject. In some embodiments, the population comprises NKX6.1-positive, ISLl-positive cells that express lower levels of FXYD2 than NKX6.1-positive, ISLl-positive cells from the pancreas of a healthy control adult subject. In some embodiments, the population comprises NKX6.1-positive, ISLl-positive cells that express higher levels of MAFB than NKX6.1-positive, ISLl-positive cells from the pancreas of a healthy control adult subject. In some embodiments, the population comprises NKX6.1-positive, ISLl-positive cells that express higher levels of SIX2, HOPX, IAPP and / or UCN3 than NKX6.1-positive, ISLl-positive cells from the pancreas of a healthy control adult subject. In some embodiments, the population comprises NKX6.1-positive, ISLl-positive cells that do not express MAFA. In some embodiments, the population comprises NKX6.1-positive, ISLl-positive cells that express MAFB. In some embodiments, as an alternative to comparing gene expression to the cells of a healthy adult pancreas, the comparison could be to the expression of genes in one or more cadaveric islets (e.g., cadaveric islets suitable for transplantation in a diabetic patient—see, e.g., Hering et al., 2016, Diabetes Care, 39(7):1230-1240) and / or primary human islet cells (e.g., primary adult human islet cells, such as those obtainable from Nordic Network for Islet Transplantation (Uppsala University) and University of Alberta IsletCore (Canada)—see, e.g., Balboa et al., 2022, Nature Biotechnology, 40:1042-1055). In some embodiments, the population comprises one or more NKX6.1-positive, ISLl-positive cells that express CHGA, MAFB, and / or ESRRG at a higher level (e.g., at least 10%, 30%, 50%, 70%, 100%, 125%, 150%, or 200% higher) than a NKX6.1-positive, ISLl-positive cell of cadaveric islets or primary human islet cells. In some embodiments, at least 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or 100% of the NKX6.1-positive, ISLl-positive cells in a population of cells express CHGA, MAFB, and / or ESRRG at a higher level than at least 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or 100% of the NKX6.1-positive, ISLl-positive cells of cadaveric islets or primary human islet cells. In some embodiments, the population comprises one or more NKX6.1-positive, ISLl-positive cells that express SIX3, MAFA, CHGB, RBP4 and / or FXYD2 at a lower level (e.g., at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100% lower) than a NKX6.1-positive, ISLl-positive cell of cadaveric islets or primary human islet cells. In some embodiments, at least 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or 100% of the NKX6.1-positive, ISLl-positive cells in a population of cells express SIX3, MAFA, CHGB, RBP4 and / or FXYD2 at a lower level than at least 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or 100% of the NKX6.1-positive, ISLl-positive cells of cadaveric islets or primary human islet cells. In some embodiments, the population comprises NKX6.1-positive, ISL1-positive cells that express lower levels of MAFA than NKX6.1-positive, ISLl-positive cells of cadaveric islets or primary human islet cells. In some embodiments, the population comprises NKX6.1-positive, ISLl-positive cells that express lower levels of SIX3 than NKX6.1-positive, ISLl-positive cells of cadaveric islets or primary human islet cells. In some embodiments, the population comprises NKX6.1-positive, ISLl-positive cells that express lower levels of CHGB than NKX6.1-positive, ISLl-positive cells of cadaveric islets or primary human islet cells. In some embodiments, the population comprises NKX6.1-positive, ISLl-positive cells that express lower levels of RBP4 than NKX6.1-positive, ISLl-positive cells of cadaveric islets or primary human islet cells. In some embodiments, the population comprises NKX6.1-positive, ISLl-positive cells that express lower levels of FXYD2 than NKX6.1-positive, ISLl-positive cells of cadaveric islets or primary human islet cells. In some embodiments, the population comprises NKX6.1-positive, ISLl-positive cells that express higher levels of MAFB than NKX6.1-positive, ISLl-positive cells of cadaveric islets or primary human islet cells. In some embodiments, the population comprises NKX6.1-positive, ISLl-positive cells that express higher levels of SIX2, HOPX, IAPP and / or UCN3 than NKX6.1-positive, ISLl-positive cells of cadaveric islets or primary human islet cells. In some embodiments, any of the NKX6.1-positive, ISLl-positive cells disclosed herein also expresses any one or more of the following genes: PC2, MNX1, or ABCC8. In some embodiments, any of the compositions or cell populations described herein comprise less than 40% VMAT1-positive cells. In some embodiments, less than 40%, 35%, 30%, 25%, 20%, 15%, or 10% of the cells in any of the compositions or cell populations disclosed herein are VMAT1-positive cells. In some embodiments, the composition or cell population comprises 1-40%, 1-35%, 1-30%, 1-25%, 1-20%, 1-15%, 1-10%, 5-40%, 5-35%, 530%, 5-25%, 5-20%, 5-15%, 5-10%, 10-40%, 10-35%, 10-30%, 10-25%, 15-25%, 10-20%, 1015%, 20-40%, 20-35%, 20-30%, 20-25%, 30-40% VMAT1-positive cells. In some embodiments, the population of cells is derived from stem cells in vitro. In some embodiments, the stem cells are genetically modified. In some embodiments, the stem cells have reduced expression of one or more of beta-2 microglobulin, CXCL10, renalase, CIITA, HLA-A, HLA-B, HLA-C, HLA-DP, HLA-DQ, and / or HLADR, relative to stem cells that are not genetically modified. In some embodiments, the stem cells have increased expression of one or more of CD47, PDL1, HLA-G, CD46, CD55, CD59 and / or CTLA, relative to stem cells that are not genetically modified. In some embodiments, the population of in vitro differentiated cells are contained in a device for implantation into a subject. Further provided herein are in vitro compositions comprising the population of in vitro differentiated cells described herein a medium. In some embodiments, the medium comprises human serum albumin. In some embodiments, the medium comprises glutamine. In some embodiments, the medium comprises any one or more of the following: an inorganic compound, an Alk5 inhibitor, a thyroid hormone receptor beta-specific agonist, a BMP type I receptor inhibitor, a RHO / ROCK pathway inhibitor, a protein kinase inhibitor, or a S-adenosylhomocysteine hydrolase inhibitor. In some embodiments, the medium comprises any one or more of the following: ZnSO4, Alk5i, GC-1, LDN-193189, thiazovivin, staurosporine, or DZNEP. In some embodiments, the medium comprises any one or more of L-glutamate, L-camitine, taurine, acetate, beta-hydroxybutarate, biotin or formate. Further provided herein are implantable encapsulation device comprising the population of in vitro differentiated cells described herein. In some embodiments, the device comprises a first membrane having a first surface comprising a plurality of channels, and a plurality of second surfaces opposing the first surface; and a second membrane opposite and attached to the plurality of the second surfaces of the first membrane. In some embodiments, the first membrane and the second membrane comprise PVDF, PTFE, ePTFE, PCL, PE / PES, PP, PS, PMMA, PLGA, PLLA, or any combination thereof. Further provided herein are implantable encapsulation devices including an internal volume comprising the composition described herein disposed therein. In some embodiments, the implantable encapsulation device comprises at least one membrane that at least partially defines the internal volume. In some embodiments, the at least one membrane includes a first membrane and a second membrane, wherein the first membrane and the second membrane are bonded together to form a seal extending at least partially around the internal volume disposed between the first membrane and the second membrane. In some embodiments, the at least one membrane comprises at least one selected from PVDF, PTFE, ePTFE, PCL, PE / PES, PP, PS, PMMA, PLGA, and PLLA. In some embodiments, the at least one membrane comprises ePTFE. In some embodiments, the device has been implanted in a subject having diabetes. In some embodiments, the subject has Type I Diabetes. Methods of treating a subject are provided, the method comprising administering to the subject a composition comprising the population of in vitro differentiated cells described herein. In some embodiments, the method comprises administering to the subject a composition comprising a population in vitro differentiated cells comprising NKX6.1-positive, ISLl-positive cells and NKX6.1-negative, ISLl-positive cells; wherein the population comprises more NKX6.1-positive, ISLl-positive cells than NKX6.1-negative, ISLl-positive cells; wherein at least 15% of the cells in the population are NKX6.1-negative, ISLl-positive cells; and wherein less than 12% of the cells in the population are NKX6.1-negative, ISLl-negative cells. In some embodiments, the method comprises implanting into the subject a implantable encapsulation device comprising a population in vitro differentiated cells comprising NKX6.1-positive, ISL1-positive cells and NKX6.1-negative, ISLl-positive cells; wherein the population comprises more NKX6.1-positive, ISLl-positive cells than NKX6.1-negative, ISLl-positive cells; wherein at least 15% of the cells in the population are NKX6.1-negative, ISLl-positive cells; and wherein less than 12% of the cells in the population are NKX6.1-negative, ISLl-negative cells. The details of one or more embodiments of the invention are set forth in the description below. Other features or advantages of the present invention will be apparent from the following drawings and detailed description of several embodiments, and also from the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings: FIG. 1 is a graph showing the blood glucose level of mice implanted with SC-islet cells differentiated using Protocol 1 or Protocol 2. SC-islet cells differentiated using Protocol 2 lowered blood glucose level in diabetic mice to a level achieved using twice the dose of SC-islet cells differentiated using Protocol 1. FIGs. 2A-2B are graphs showing oral glucose tolerance test (OGTT) results of mice transplanted with SC-islet cells differentiated using Protocol 1 or Protocol 2. FIG. 2A shows glucose levels up to 180 minutes post-glucose administration. FIG. 2B shows Area Under the Curve (AUC) derived from the oral glucose tolerance test (OGTT). FIGs. 3A-3C are graphs showing the percentage of C-peptide positive cells (P cells), glucagon positive cells (a cells) and somatostatin positive cells (6 cells) in kidneys grafts of mice implanted with SC-islet cells differentiated using Protocol 1 (Group 3 and Group 4) or Protocol 2 (Group 5). Groups 3 and 5 were implanted with 4 million SC-islet cells, while Group 4 was implanted with 8 million SC-islet cells. FIGs. 4A-4B are graphs showing the percentage of serotonin positive cells (FIG. 4A) and percentage of proliferating EC cells (FIG. 4B) in the kidney grafts of mice implanted with SC-islet cells differentiated using Protocol 1 (Group 3 and Group 4) or Protocol 2 (Group 5). Groups 3 and 5 were implanted with 4 million SC-islet cells, while Group 4 was implanted with 8 million SC-islet cells. FIG. 5 is a graph showing the percentage of Ki67 positive cells in the kidney grafts of mice implanted with SC-islet cells differentiated using Protocol 1 (Group 3 and Group 4) or Protocol 2 (Group 5). Groups 3 and 5 were implanted with 4 million SC-islet cells, while Group 4 was implanted with 8 million SC-islet cells. FIGs. 6A-6C are graphs showing the percentage of SOX9 positive cells (FIG. 6A), Ki67 positive cells (FIG. 6B), and SOX9 positive, Ki67 positive cells (FIG. 6C) in the kidney grafts of mice implanted with SC-islet cells differentiated using Protocol 1 (Group 3 and Group 4) or Protocol 2 (Group 5). Groups 3 and 5 were implanted with 4 million SC-islet cells, while Group 4 was implanted with 8 million SC-islet cells. FIG. 7 is a graph showing the quantification of neo-vascularization in kidney grafts of mice implanted with SC-islet cells differentiated using Protocol 1 (Group 3 and Group 4) or Protocol 2 (Group 5). Neovascularization was indicated by CD31 expression level. Groups 3 and 5 were implanted with 4 million SC-islet cells, while Group 4 was implanted with 8 million SC-islet cells. FIGs. 8A-8B are flow cytometry graphs showing the percentage of ISL1+ cells in S6 SC-islets. SC-islets differentiated using Protocol 2 (FIG. 8B) showed increased ISL1+ cells as compared with SC-islets differentiated using Protocol 1 (FIG. 8A). FIGs. 9A-9B are flow cytometry graphs showing ISL1 / NKX6.1 expression in pancreatic progenitor cells differentiated using Protocol 1 (FIG. 9A) or using Protocol 1 with the addition of a FoxOl inhibitor on S4D5 (FIG. 9B). FIGs. 10A-10B are flow cytometry graphs showing ISL1 / Nkx6.1 expression in pancreatic progenitor cells progenitor differentiated using Protocol 1 (FIG. 10A) or using Protocol 1 with the addition of a Wnt inhibitor (XAV) on S5 Days 1-4 (FIG. 10B). FIGs. 11A-11B are flow cytometry graphs showing ISL1 / NKX6.1 expression in pancreatic progenitor cells differentiated using Protocol 1 with the addition of a FoxOl inhibitor on S4D5 (FIG. 11A) or with the addition of a FoxOl inhibitor on S4D5 and a Wnt inhibitor (XAV) on S5 Days 1-4 (FIG. 11B). FIGs. 12A-12B are flow cytometry graphs showing ISL1 / NKX6.1 expression in pancreatic progenitor cells differentiated using Protocol 1 (FIG. 12A) or using Protocol 1 with the addition of a PKC activator (TPB) on S4D5 and S5 Days 1 and 2 (FIG. 12B). FIGs. 13A-13B are flow cytometry graphs showing ISL1 / NKX6.1 expression in pancreatic progenitor cells differentiated using Protocol 1 (FIG. 13A) or using Protocol 1 with the addition of a PKC activator (TPB) and a Notch inhibitor (XXI) on S4D5 followed by a PKC activator (TPB) alone on S5 Days 1-4 (FIG. 13B). FIGs. 14A-14B are flow cytometry graphs showing ISL1 / NKX6.1 expression in pancreatic progenitor cells differentiated using Protocol 1 with the addition of a FoxOl inhibitor, PKC activator (TPB), and a Notch inhibitor (XXI) on S4D5 (FIG. 14A) or with the addition of a FoxOl inhibitor, PKC activator (TPB), and a Notch inhibitor (XXI) on S4D5 followed by a PKC activator (TPB) and a Wnt inhibitor (XAV) on S5 Days 1-4 (FIG. 14B). FIGs. 15A-15C are flow cytometry graphs showing ISL1 / NKX6.1 expression in pancreatic progenitor cells differentiated using Protocol 1 with the addition of a PKC activator (PDBU) on S4D5 (FIG. 15A), using Protocol 1 with the addition of a FoxOl inhibitor, a PKC activator (PDBU) and a Notch inhibitor (XXI) on S4D5 (FIG. 15B), or using Protocol 1 with the addition of a FoxOl inhibitor, a PKC activator (PDBU) and a Notch inhibitor (XXI) on S4D5 followed by a Wnt inhibitor (XAV) on S5 Days 1-4 (FIG. 15C). FIGs. 16A-16H are flow cytometry graphs showing ISL1 / NKX6.1 expression on S6D4 in SC-islet cells differentiated using the methods described in Table 6. FIGs. 17A-17H are flow cytometry graphs showing Chromogranin A (CHGA) / C-Peptide expression on S6D4 in SC-islet cells differentiated using the methods described in Table 6. FIGs. 18A-18H are flow cytometry graphs showing SOX9 / Ki67 expression on S6D4 in SC-islet cells differentiated using the methods described in Table 6. FIGs. 19A-19H are flow cytometry graphs showing ISL1 / NKX6.1 expression on S6D7 in SC-islet cells differentiated using the methods described in Table 6. FIGs. 20A-20H are flow cytometry graphs showing Chromogranin A (CHGA) / C-Peptide expression on S6D7 in SC-islet cells differentiated using the methods described in Table 6. FIGs. 21A-21H are flow cytometry graphs showing Glucagon (GCG) / Somatostatin (SST) expression on S6D7 in SC-islet cells differentiated using the methods described in Table 6. FIGs. 22A-22H are flow cytometry graphs showing ISL1 / NKX6.1 expression on S6D12 in SC-islet cells differentiated using the methods described in Table 6. FIGs. 23A-23H are flow cytometry graphs showing Chromogranin A (CHGA) / C-Peptide expression on S6D12 in SC-islet cells differentiated using the methods described in Table 6. FIGs. 24A-24H are flow cytometry graphs showing Glucagon (GCG) / Somatostatin (SST) expression on S6D12 in SC-islet cells differentiated using the methods described in Table 6. FIGs. 25A-25B are graphs showing the percentage of ISL1+ cells (FIG. 25A) and percentage of SC-EC cells (FIG. 25B) in SC-islets differentiated using Protocol 1, Protocol 2, or Protocol 3. SC-islets differentiated using Protocol 2 or Protocol 3 show increased total ISL1+ cells and reduced ISLl- cells (SC-EC cells). FIGs. 26A-26C are flow cytometry graphs showing ISL1 / NKX6.1 expression on S6D4 in SC-islet cells differentiated using Protocol 1 (FIG. 26A), Protocol 2 (FIG. 26B), or Protocol 3 (FIG. 26C). FIG. 27 shows a graph of cell density throughout differentiation using Protocol 1, Protocol 2, or Protocol 3. “Spinner” indicates the cells were cultured in spinner flasks, while “3-MAG” indicates the cells were cultured in a 3-liter reactor. FIGs. 28A-28B is a graph showing the C-peptide (FIG. 28A) and glucagon (FIG. 28B) content of SC-islet cells differentiated using Protocol 1 (Table 2), Protocol 2 (Table 2), or Protocol 3 (Table 9). FIGs. 29A-29D are flow cytometry graphs showing ISL1 / Nkx6.1 expression on S6D3 in SC-islet cells differentiated using Protocol 1 (FIG. 29A), Protocol 2 (FIG. 29B), Protocol 3 (FIG. 29C), or Protocol 3 with the addition of FGF2 (at 100 ng / ml) in stage 6 media (Media A shown in Table 7A) (FIG. 29D). FIGs. 30A-30D are flow cytometry graphs showing Aristaless related homeobox (ARX) / Glucagon (GCG) expression on S6D3 in SC-islet cells differentiated using Protocol 1 (FIG. 30A), Protocol 2 (FIG. 30B), Protocol 3 (FIG. 30C), or Protocol 3 with the addition of FGF2 (at 100 ng / ml) in stage 6 media (Media A shown in Table 7A) (FIG. 30D). FIGs. 31A-31D are flow cytometry graphs showing Chromogranin A (CHGA) / Nkx6.1 expression on S6D3 in SC-islet cells differentiated using Protocol 1 (FIG. 31A), Protocol 2 (FIG. 31B), Protocol 3 (FIG. 31C), or Protocol 3 with the addition of FGF2 (at 100 ng / ml) in stage 6 media (Media A shown in Table 7A) (FIG. 31D). FIGs. 32A-32D are flow cytometry graphs showing SOX9 / Ki67 expression on S6D3 in SC-islet cells differentiated using Protocol 1 (FIG. 32A), Protocol 2 (FIG. 32B), Protocol 3 (FIG. 32C), or Protocol 3 with the addition of FGF2 (at 100 ng / ml) in stage 6 media (Media A shown in Table 7A) (FIG. 32D). FIGs. 33A-33D are flow cytometry graphs showing ISL1 / Nkx6.1 expression on S6D7 in SC-islet cells differentiated using Protocol 1 (FIG. 33A), Protocol 2 (FIG. 33B), Protocol 3 (FIG. 33C), or Protocol 3 with the addition of FGF2 (at 100 ng / ml) in stage 6 media (Media A shown in Table 7A) (FIG. 33D). FIGs. 34A-34D are flow cytometry graphs showing ISL1 / Nkx6.1 expression on S6D11 in SC-islet cells differentiated using Protocol 1 (FIG. 34A), Protocol 2 (FIG. 34B), Protocol 3 (FIG. 34C), or Protocol 3 with the addition of FGF2 (at 100 ng / ml) in stage 6 media (Media A shown in Table 7A) (FIG. 34D). FIGs. 35A-35B are graphs showing human C-Peptide level (FIG. 35A) and human glucagon level (FIG. 35B) in SC-islet cells differentiated using Protocol 1, Protocol 2, Protocol 3, or Protocol 3 with the addition of FGF2 (at 100 ng / ml) in stage 6 media (Media A shown in Table 7A). DETAILED DESCRIPTION The following description and examples illustrate embodiments of the present disclosure in detail. It is to be understood that this disclosure is not limited to the particular embodiments described herein and as such can vary. Those of skill in the art will recognize that there are numerous variations and modifications of this disclosure, which are encompassed within its scope. All terms are intended to be understood as they would be understood by a person skilled in the art. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure pertains. The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described. Although various features of the present disclosure can be described in the context of a single embodiment, the features can also be provided separately or in any suitable combination. Conversely, although the present disclosure can be described herein in the context of separate embodiments for clarity, the present disclosure can also be implemented in a single embodiment. The following definitions supplement those in the art and are directed to the current application and are not to be imputed to any related or unrelated case, e.g., to any commonly owned patent or application. Although any methods and materials similar or equivalent to those described herein can be used in the practice for testing of the present disclosure, the preferred materials and methods are described herein. Accordingly, the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. In this application, the use of the singular includes the plural unless specifically stated otherwise. It must be noted that, as used in the specification, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. In this application, the use of “or” means “and / or” unless stated otherwise. The terms “and / or” and “any combination thereof’ and their grammatical equivalents as used herein, can be used interchangeably. These terms can convey that any combination is specifically contemplated. Solely for illustrative purposes, the following phrases “A, B, and / or C” or “A, B, C, or any combination thereof’ can mean “A individually; B individually; C individually; A and B; B and C; A and C; and A, B, and C.” The term “or” can be used conjunctively or disjunctively, unless the context specifically refers to a disjunctive use. WO 2023 / 077140                                                 PCT / US2022 / 079017 Furthermore, use of the term “including” as well as other forms, such as “include”, “includes,” and “included,” is not limiting. Reference in the specification to “some embodiments,” “an embodiment,” “one embodiment” or “other embodiments” means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least some embodiments, but not necessarily all embodiments, of the present disclosures. As used in this specification and claim(s), the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps. It is contemplated that any embodiment discussed in this specification can be implemented with respect to any method or composition of the present disclosure, and vice versa. Furthermore, compositions of the present disclosure can be used to achieve methods of the present disclosure. The term “about” or “approximately” means within an acceptable error range for the particular value as determined by one of ordinary skill in the art, which will depend in part on how the value is measured or determined, e.g., the limitations of the measurement system. For example, “about” can mean within 1 or more than 1 standard deviation, per the practice in the art. Alternatively, “about” can mean a range of up to 20%, up to 10%, up to 5%, or up to 1% of a given value. In another example, the amount “about 10” includes 10 and any amounts from 9 to 11. In yet another example, the term “about” in relation to a reference numerical value can also include a range of values plus or minus 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1% from that value. Alternatively, particularly with respect to biological systems or processes, the term “about” can mean within an order of magnitude, preferably within 5-fold, and more preferably within 2-fold, of a value. Where particular values are described in the application and claims, unless otherwise stated the term “about” meaning within an acceptable error range for the particular value should be assumed. The term “diabetes” and its grammatical equivalents as used herein can refer to is a disease characterized by high blood sugar levels over a prolonged period. For example, the term “diabetes” and its grammatical equivalents as used herein can refer to all or any type of diabetes, including, but not limited to, type 1, type 2, cystic fibrosis-related, surgical, gestational diabetes, and mitochondrial diabetes. In some embodiments, diabetes can be a form of hereditary diabetes. In some embodiments, diabetes can be an autoimmune form of diabetes. The term “endocrine cell(s),” if not particularly specified, can refer to hormone-producing cells present in the pancreas of an organism, such as “islet”, “islet cells”, “islet equivalent”, “islet-like cells”, “pancreatic islets” and their grammatical equivalents. In an embodiment, the endocrine cells can be differentiated from pancreatic progenitor cells or precursors. Islet cells can comprise different types of cells, including, but not limited to, pancreatic a cells, pancreatic P cells, pancreatic 6 cells, pancreatic F cells, and / or pancreatic a cells. Islet cells can also refer to a group of cells, cell clusters, or the like. The terms “progenitor” and “precursor” cell are used interchangeably herein and refer to cells that have a cellular phenotype that is more primitive (e.g., is at an earlier step along a developmental pathway or progression than is a fully differentiated cell) relative to a cell which it can give rise to by differentiation. Often, progenitor cells can also have significant or very high proliferative potential. Progenitor cells can give rise to multiple distinct differentiated cell types or to a single differentiated cell type, depending on the developmental pathway and on the environment in which the cells develop and differentiate. A “precursor thereof’ as the term related to an insulin-positive endocrine cell can refer to any cell that is capable of differentiating into an insulin-positive endocrine cell, including for example, a pluripotent stem cell, a definitive endoderm cell, a primitive gut tube cell, a pancreatic progenitor cell, or endocrine progenitor cell, that if cultured under suitable conditions will differentiate the precursor cell into the insulin-positive endocrine cell. The terms “stem cell-derived P cell,” “SC-P cell,” “functional P cell,” “functional pancreatic P cell,” “mature SC-P cell,” “P-like cell” and their grammatical equivalents can refer to cells (e.g., non-native pancreatic P cells) that display at least one marker indicative of a pancreatic P cell (e.g., PDX-1 or NKX6.1), expresses insulin, and display a glucose stimulated insulin secretion (GSIS) response similar or superior to that of an endogenous mature P cell (e.g., a mature P from a healthy functioning pancreas from a healthy adult non-diabetic patient). For simplicity, SC-P cells may be referred to as simply “P cells” in this disclosure. In some embodiments, the terms “SC-P cell” and “non-native P cell” as used herein are interchangeable. In some embodiments, the “SC-P cell” expresses lower levels of MAFA than a pancreatic P cell from a healthy adult human patient. In some embodiments, the “SC-P cell” expresses higher levels of MAFB than a pancreatic P cell from a healthy adult human patient. In some embodiments, the “SC-P cell” expresses higher levels of SIX2, HOPX, IAPP and / or UCN3 than a pancreatic P cell from a healthy adult human patient. In some embodiments, the “SC-P cell” comprises a mature pancreatic cell. It is to be understood that the SC-P cells need not be derived (e.g., directly) from stem cells, as the methods of the disclosure are capable of deriving SC-P cells from any insulin-positive endocrine cell or precursor thereof using any cell as a starting point (e.g., one can use embryonic stem cells, induced-pluripotent stem cells, progenitor cells such as definitive endoderm cells, partially reprogrammed somatic cells (e.g., a somatic cell which has been partially reprogrammed to an intermediate state between an induced pluripotent stem cell and the somatic cell from which it was derived), multipotent cells, totipotent cells, a transdifferentiated version of any of the foregoing cells, etc., as the invention is not intended to be limited in this manner). In some embodiments, the SC-P cells exhibit a response to multiple glucose challenges (e.g., at least one, at least two, or at least three or more sequential glucose challenges). In some embodiments, the response resembles the response of endogenous islets (e.g., human islets) to multiple glucose challenges. In some embodiments, the morphology of the SC-P cell resembles the morphology of an endogenous P cell. In some embodiments, the SC-P cell exhibits an in vitro GSIS response that resembles the GSIS response of an endogenous P cell. In some embodiments, the SC-P cell exhibits an in vivo GSIS response that resembles the GSIS response of an endogenous P cell. In some embodiments, the SC-P cell exhibits both an in vitro and in vivo GSIS response that resembles the GSIS response of an endogenous P cell. In some embodiments, the GSIS response of the SC-P cell can be observed within two weeks of transplantation of the SC-P cell into a host (e.g., a human or animal). In some embodiments, the GSIS response of the SC-P cell can be observed within three weeks of transplantation of the SC-P cell into a host (e.g., a human or animal). In some embodiments, the GSIS response of the SC-P cell can be observed within four weeks of transplantation of the SC-P cell into a host (e.g., a human or animal). In some embodiments, the GSIS response of the SC-P cell can be observed between one month and three months of transplantation of the SC-P cell into a host (e.g., a human or animal). In some embodiments, the SC-P cells package insulin into secretory granules. In some embodiments, the SC-P cells exhibit encapsulated crystalline insulin granules when viewed using electron microscopy. In some embodiments, the SC-P cells exhibit a stimulation index of greater than 1. In some embodiments, the SC-P cells exhibit a stimulation index of greater than 1.1. In some embodiments, the SC-P cells exhibit a stimulation index of greater than 2. In some embodiments, the stimulation index of the cell is characterized by the ratio of insulin secreted in response to high glucose concentrations (e.g., 15 mM) compared to low glucose concentrations (e.g., 2.5 mM). In some embodiments, the SC-P cells exhibit cytokine-induced apoptosis in response to cytokines. In some embodiments, insulin secretion from the SC-P cells is enhanced in response to known antidiabetic drugs (e.g., secretagogues). In some embodiments, the SC-P cells are monohormonal. In some embodiments, the SC-P cells do not abnormally co-express other hormones, such as glucagon, somatostatin or pancreatic polypeptide. In some embodiments, the SC-P cells exhibit a low rate of replication. In some embodiments, the SC-P cells increase intracellular Ca2+ in response to glucose. The terms “stem cell-derived a cell,” “SC-a cell,” “functional a cell,” “functional pancreatic a cell,” “mature SC-a cell,” “a-like cell” and their grammatical equivalents can refer to cells (e.g., non-native pancreatic a cells) that display at least one marker indicative of a pancreatic a cell (e.g., glucagon, expressing ISL1 but not NKX6.1), expresses glucagon, and is capable of secreting functional glucagon in response to a stimulus that induces an endogenous pancreatic a cell to secrete functional glucagon. In some embodiments, the “SC-a cell” does not express somatostatin. In some embodiments, the “SC-a cell” does not express insulin. In some embodiments, the terms “SC-a cell” and “non-native a cell” as used herein are interchangeable. In some embodiments, the “SC-a cell” comprises a mature pancreatic cell. For short, these cells may be referred to as simply “a cells” in this disclosure. The terms “stem cell-derived 6 cell,” “SC-6 cell,” “functional 6 cell,” “functional pancreatic 6 cell,” “mature SC-6 cell,” “6-like cell” and their grammatical equivalents can refer to cells (e.g., non-native pancreatic 6 cells) that display at least one marker indicative of a pancreatic 6 cell (e.g., somatostatin), expresses and is capable of secreting somatostatin in response to a stimulus that induces an endogenous pancreatic 6 cell to secrete functional glucagon. For simplicity, SC- 6 cells may be referred to as simply “6 cells” in this disclosure. In some embodiments, “SC-6 cell” does not express glucagon. In some embodiments, “SC-6 cell” does not express insulin. In some embodiments, the terms “SC-6 cell” and “non-native 6 cell” as used herein are interchangeable. In some embodiments, the “SC-6 cell” comprises a mature pancreatic cell. The terms “stem cell-derived enterochromaffin (EC) cell,” “SC-EC cell,” and their grammatical equivalents can refer to cells (e.g., non-native pancreatic EC cells) that display at least one marker indicative of a pancreatic EC cell (e.g., VMAT1 (vesicular monoamine transporter 1), expressing NKX6.1 but not ISL1). In some embodiments, the terms “SC-EC cell” and “non-native EC cell” as used herein are interchangeable. Similar to SC-P cells, it is to be understood that the SC-a, SC-6 cells, and SC-EC cells need not be derived (e.g., directly) from stem cells, as the methods of the disclosure are capable of deriving SC-a cells from other precursor cells generated during in vitro differentiation of SC-P cells as a starting point (e.g., one can use embryonic stem cells, induced-pluripotent stem cells, progenitor cells, partially reprogrammed somatic cells (e.g., a somatic cell which has been partially reprogrammed to an intermediate state between an induced pluripotent stem cell and the somatic cell from which it was derived), multipotent cells, totipotent cells, a transdifferentiated version of any of the foregoing cells, etc., as the invention is not intended to be limited in this manner). As used herein, the term “insulin producing cell” and its grammatical equivalent refer to a cell differentiated from a pancreatic progenitor, or precursor thereof, which secretes insulin. An insulin-producing cell can include pancreatic P cell as that term is described herein, as well as pancreatic P-like cells (e.g., insulin-positive, endocrine cells) that synthesize (e.g., transcribe the insulin gene, translate the proinsulin mRNA, and modify the proinsulin mRNA into the insulin protein), express (e.g., manifest the phenotypic trait carried by the insulin gene), or secrete (release insulin into the extracellular space) insulin in a constitutive or inducible manner. A population of insulin producing cells e.g., produced by differentiating insulin-positive endocrine cells or a precursor thereof into SC-P cells according to the methods of the present disclosure can be pancreatic P cells or P-like cells (e.g., cells that have at least one, or at least two least characteristics of an endogenous P cell and exhibit a glucose stimulated insulin secretion (GSIS) response that resembles an endogenous adult P cell). The population of insulin-producing cells, e.g., produced by the methods as disclosed herein can comprise mature pancreatic P cell or SC-P cells, and can also contain non-insulin-producing cells (e.g., cells of cell like phenotype with the exception they do not produce or secrete insulin). The terms “insulin-positive P-like cell,” “insulin-positive endocrine cell,” and their grammatical equivalents can refer to cells (e.g., pancreatic endocrine cells) that display at least one marker indicative of a pancreatic P cell and also expresses insulin but, unless specified otherwise, lack a glucose stimulated insulin secretion (GSIS) response characteristic of an endogenous P cell. Exemplary markers of “insulin-positive endocrine cell” include, but are not limited to, NKX6.1 (NK6 homeobox 1), ISL1 (Isletl), and insulin. The term “P cell marker” refers to, without limitation, proteins, peptides, nucleic acids, polymorphism of proteins and nucleic acids, splice variants, fragments of proteins or nucleic acids, elements, and other analyte which are expressed or present in pancreatic P cells. Exemplary P cell markers include, but are not limited to, pancreatic and duodenal homeobox 1 (PDX1) polypeptide, insulin, c-peptide, amylin, E-cadherin, Hnf3p, PCV3, B2, Nkx2.2, GLUT2, PC2, ZnT-8, ISL1, Pax6, Pax4, NeuroD, 1 Infib, Hnf-6, Hnf-3beta, VMAT2, NKX6.1, and MafA, and those described in Zhang et al., Diabetes. 50(10):2231-6 (2001). In some embodiments, the P cell marker is a nuclear P-cell marker. In some embodiments, the P cell marker is PDX1 or PH3. The term “pancreatic endocrine marker” can refer to without limitation, proteins, peptides, nucleic acids, polymorphism of proteins and nucleic acids, splice variants, fragments of proteins or nucleic acids, elements, and other analytes which are expressed or present in pancreatic endocrine cells. Exemplary pancreatic endocrine cell markers include, but are not limited to, Ngn-3, NeuroD and Islet-1. The term “pancreatic progenitor,” “pancreatic endocrine progenitor,” “pancreatic precursor,” “pancreatic endocrine precursor” and their grammatical equivalents are used interchangeably herein and can refer to a stem cell which is capable of becoming a pancreatic hormone expressing cell capable of forming pancreatic endocrine cells, pancreatic exocrine cells or pancreatic duct cells. These cells are committed to differentiating towards at least one type of pancreatic cell, e.g. P cells that produce insulin; a cells that produce glucagon; 6 cells (or D cells) that produce somatostatin; and / or F cells that produce pancreatic polypeptide. Such cells can express at least one of the following markers: NGN3, NKX2.2, NeuroD, ISL-1, Pax4, Pax6, or ARX. The term “PDXl-positive pancreatic progenitor” as used herein can refer to a cell which is a pancreatic endoderm (PE) cell which has the capacity to differentiate into SC-P cells, such as pancreatic P cells. A PDX1-positive pancreatic progenitor expresses the marker PDX1. Other markers include, but are not limited to Cdcpl, or Ptfla, or HNF6 or NRx2.2. The expression of PDX1 may be assessed by any method known by the skilled person such as immunochemistry using an anti-PDXl antibody or quantitative RT-PCR. In some embodiments, a PDXl-positive pancreatic progenitor cell lacks expression of NKX6.1. In some embodiments, a PDXl-positive pancreatic progenitor cell can also be referred to as PDXl-positive, NKX6.1-negative pancreatic progenitor cell due to its lack of expression of NKX6.1. In some embodiments, the PDXl-positive pancreatic progenitor cells can also be termed as “pancreatic foregut endoderm cells.” The terms “PDXl-positive, NKX6.1-positive pancreatic progenitor,” and “NKX6.1-positive pancreatic progenitor” are used interchangeably herein and can refer to a cell which is a pancreatic endoderm (PE) cell which has the capacity to differentiate into insulin-producing cells, such as pancreatic P cells. A PDXl-positive, NKX6.1-positive pancreatic progenitor expresses the markers PDX1 and NKX6-1. Other markers may include, but are not limited to Cdcpl, or Ptfla, or HNF6 or NRx2.2. The expression of NKX6-1 may be assessed by any method known by the skilled person such as immunochemistry using an anti-NKX6-l antibody or quantitative RT-PCR. As used herein, the terms “NKX6.1” and “NKX6-1” are equivalent and interchangeable. In some embodiments, the PDXl-positive, NKX6.1-positive pancreatic progenitor cells can also be termed as “pancreatic foregut precursor cells.” The terms “NeuroD” and “NeuroD 1” are used interchangeably and identify a protein expressed in pancreatic endocrine progenitor cells and the gene encoding it. The term “differentiated cell” or its grammatical equivalents means any primary cell that is not, in its native form, pluripotent as that term is defined herein. Stated another way, the term “differentiated cell” can refer to a cell of a more specialized cell type derived from a cell of a less specialized cell type (e.g., a stem cell such as an induced pluripotent stem cell) in a cellular differentiation process. Without wishing to be limited to theory, a pluripotent stem cell in the course of normal ontogeny can differentiate first to an endoderm cell that is capable of forming pancreas cells and other endoderm cell types. Further differentiation of an endoderm cell may lead to the pancreatic pathway, where -98% of the cells become exocrine, ductular, or matrix cells, and -2% become endocrine cells. Early endocrine cells are islet progenitors, which can then differentiate further into insulin-producing cells (e.g. functional endocrine cells) which secrete insulin, glucagon, somatostatin, or pancreatic polypeptide. Endoderm cells can also be differentiated into other cells of endodermal origin, e.g. lung, liver, intestine, thymus etc. As used herein, the term “somatic cell” can refer to any cells forming the body of an organism, as opposed to germline cells. In mammals, germline cells (also known as “gametes”) are the spermatozoa and ova which fuse during fertilization to produce a cell called a zygote, from which the entire mammalian embryo develops. Every other cell type in the mammalian body - apart from the sperm and ova, the cells from which they are made (gametocytes) and undifferentiated stem cells - is a somatic cell: internal organs, skin, bones, blood, and connective tissue are all made up of somatic cells. In some embodiments the somatic cell is a “non-embryonic somatic cell”, by which is meant a somatic cell that is not present in or obtained from an embryo and does not result from proliferation of such a cell in vitro. In some embodiments the somatic cell is an “adult somatic cell”, by which is meant a cell that is present in or obtained from an organism other than an embryo or a fetus or results from proliferation of such a cell in vitro. Unless otherwise indicated the methods for converting at least one insulin-positive endocrine cell or precursor thereof to an insulin-producing, glucose responsive cell can be performed both in vivo and in vitro (where in vivo is practiced when at least one insulin-positive endocrine cell or precursor thereof are present within a subject, and where in vitro is practiced using an isolated at least one insulin-positive endocrine cell or precursor thereof maintained in culture). As used herein, the term “adult cell” can refer to a cell found throughout the body after embryonic development. The term “endoderm cell” as used herein can refer to a cell which is from one of the three primary germ cell layers in the very early embryo (the other two germ cell layers are the mesoderm and ectoderm). The endoderm is the innermost of the three layers. An endoderm cell differentiates to give rise first to the embryonic gut and then to the linings of the respiratory and digestive tracts (e.g., the intestine), the liver and the pancreas. The term “a cell of endoderm origin” as used herein can refer to any cell which has developed or differentiated from an endoderm cell. For example, a cell of endoderm origin includes cells of the liver, lung, pancreas, thymus, intestine, stomach and thyroid. Without wishing to be bound by theory, liver and pancreas progenitors (also referred to as pancreatic progenitors) are developed from endoderm cells in the embryonic foregut. Shortly after their specification, liver and pancreas progenitors rapidly acquire markedly different cellular functions and regenerative capacities. These changes are elicited by inductive signals and genetic regulatory factors that are highly conserved among vertebrates. Interest in the development and regeneration of the organs has been fueled by the intense need for hepatocytes and pancreatic P cells in the therapeutic treatment of liver failure and type I diabetes. Studies in diverse model organisms and humans have revealed evolutionarily conserved inductive signals and transcription factor networks that elicit the differentiation of liver and pancreatic cells and provide guidance for how to promote hepatocyte and P cell differentiation from diverse stem and progenitor cell types. The term “definitive endoderm” as used herein can refer to a cell differentiated from an endoderm cell and which can be differentiated into a SC-P cell (e.g., a pancreatic P cell). A definitive endoderm cell expresses the marker Soxl7. Other markers characteristic of definitive endoderm cells may include, but are not limited to MIXL2, GATA4, HNF3b, GSC, FGF17, VWF, CALCR, FOXQ1, CXCR4, Cerberus, OTX2, goosecoid, C-Kit, CD99, CMK0R1 and CRIP1. In particular, definitive endoderm cells herein express Soxl7 and in some embodiments Soxl7 and HNF3B, and do not express significant levels of GATA4, SPARC, APF or DAB. Definitive endoderm cells are not positive for the marker PDX1 (e.g. they are PDX1-negative). Definitive endoderm cells have the capacity to differentiate into cells including those of the liver, lung, pancreas, thymus, intestine, stomach and thyroid. The expression of Soxl7 and other markers of definitive endoderm may be assessed by any method known by the skilled person such as immunochemistry, e.g., using an anti-Soxl7 antibody, or quantitative RT-PCR. The term “pancreatic endoderm” can refer to a cell of endoderm origin which is capable of differentiating into multiple pancreatic lineages, including pancreatic P cells, but no longer has the capacity to differentiate into non-pancreatic lineages. The term “pancreatic islet cells” refers to a population of cells that include different types of pancreatic endocrine cells (P-cells, a-cells, 6-cells, s-cells) and enterochromaffin (EC) cells, e.g., as described in Xavier et al. (J Clin Med. 2018 Mar; 7(3): 54), incorporated herein by reference. The term “primitive gut tube cell” or “gut tube cell” as used herein can refer to a cell differentiated from an endoderm cell and which can be differentiated into a SC-P cell (e.g., a pancreatic P cell). A primitive gut tube cell expresses at least one of the following markers: HNP1-P, HNF3-P or HNF4-a. In some embodiments, a primitive gut tube cell is FOXA2- positive and SOX2-positive, i.e., expresses both FOXA2 (also known as HNF3-P) and SOX2. In some embodiments, a primitive gut tube cell is FOXA2-positive and PDX1-negative, i.e., expresses FOXA2 but not PDX1. Primitive gut tube cells have the capacity to differentiate into cells including those of the lung, liver, pancreas, stomach, and intestine. The expression of HNF1-P and other markers of primitive gut tube may be assessed by any method known by the skilled person such as immunochemistry, e.g., using an anti-HNFl-P antibody. The term “phenotype” can refer to one or a number of total biological characteristics that define the cell or organism under a particular set of environmental conditions and factors, regardless of the actual genotype. The terms “patient,” “subject,” and “individual” may be used interchangeably and refer to either a human or a non-human animal. The “non-human animals” and “non-human mammals” as used interchangeably herein, includes mammals such as rats, mice, rabbits, sheep, cats, dogs, cows, pigs, and non-human primates. The term “subject” also encompasses any vertebrate including but not limited to mammals, reptiles, amphibians and fish. However, advantageously, the subject is a mammal such as a human, or other mammals such as a domesticated mammal, e.g., dog, cat, horse, and the like, or production mammal, e.g. cow, sheep, pig, and the like. “Patient in need thereof’ or “subject in need thereof’ is referred to herein as a patient diagnosed with or suspected of having a disease or disorder, for instance, but not restricted to diabetes. “Administering” as used herein can refer to providing one or more compositions described herein to a patient or a subject. By way of example and not limitation, composition administration, e.g., injection, can be performed by intravenous (i.v.) injection, sub-cutaneous (s.c.) injection, intradermal (i.d.) injection, intraperitoneal (i.p.) injection, or intramuscular (i.m.) injection. One or more such routes can be employed. Parenteral administration can be, for example, by bolus injection or by gradual perfusion over time. Alternatively, or concurrently, administration can be by the oral route. Additionally, administration can also be by surgical deposition of a bolus or pellet of cells, or positioning of a medical device. In an embodiment, a composition of the present disclosure can comprise engineered cells or host cells expressing nucleic acid sequences described herein, or a vector comprising at least one nucleic acid sequence described herein, in an amount that is effective to treat or prevent proliferative disorders. A pharmaceutical composition can comprise the cell population as described herein, in combination with one or more pharmaceutically or physiologically acceptable carriers, diluents or excipients. Such compositions can comprise buffers such as neutral buffered saline, phosphate buffered saline and the like; carbohydrates such as glucose, mannose, sucrose or dextrans, mannitol; proteins; polypeptides or amino acids such as glycine; antioxidants; chelating agents such as EDTA or glutathione; adjuvants (e.g., aluminum hydroxide); and preservatives. The ranges disclosed throughout are sometimes referred to as, for example, “X is administered on or on about day 1 to 2; or 2 to 3 [or any numerical range].” This range includes the numbers themselves (e.g., the endpoints of the range) and any individual numbers present in this range. All these different combinations are contemplated by the ranges disclosed throughout. All disclosed ranges should be interpreted in this manner, whether it refers to an administration of a therapeutic agent or referring to days, months, years, weight, dosage amounts, etc., unless otherwise specifically indicated to the contrary. Differentiation stages Pancreatic differentiation as disclosed herein may be carried out in a step-wise manner. In an exemplary embodiment of the step-wise progression, “Stage 1” or “SI” or “Stl” refers to the first step in the differentiation process, the differentiation of pluripotent stem cells into cells expressing markers characteristic of definitive endoderm cells (“DE”, “Stage 1 cells” or “Stl cells” or “SI cells”). “Stage 2” or “S2” or “St2” refers to the second step, the differentiation of cells expressing markers characteristic of definitive endoderm cells into cells expressing markers characteristic of gut tube cells (“GT”, “Stage 2 cells” or “St2 cells” or “S2 cells”). “Stage 3” or “S3” or “St3” refers to the third step, the differentiation of cells expressing markers characteristic of gut tube cells into cells expressing markers characteristic of pancreatic progenitor 1 cells (“PPI”, “Stage 3 cells” or “St3 cells” or “S3 cells”). “Stage 4” or “S4” or “St4” refers to the fourth step, the differentiation of cells expressing markers characteristic of pancreatic progenitor 1 cells into cells expressing markers characteristic of pancreatic progenitor 2 cells (“PP2”, “Stage 4 cells” or “St4 cells” or “S4 cells”). “Stage 5” or “S5” or “St5” refers to the fifth step, the differentiation of cells expressing markers characteristic of pancreatic progenitor 2 cells (e.g., PDX.1+, NKX6.1+) into cells expressing markers characteristic of pancreatic endoderm cells and / or pancreatic endocrine progenitor cells (e.g., insulin+) (“EN”, “Stage 5 cells” or “St5 cells” or “S5 cells”). “Stage 6” or “S6” or “St6” refers to the differentiation of cells expressing markers characteristic of pancreatic endocrine progenitor cells (e.g., insulin) into cells expressing markers characteristic of pancreatic endocrine P cells (“SC-P cells”) or pancreatic endocrine a cells (“SC-a cells”). It should be appreciated, however, that not all cells in a particular population progress through these stages at the same rate, i.e., some cells may have progressed less, or more, down the differentiation pathway than the majority of cells present in the population. For example, in some embodiments, SC-P cells can be identified during stage 5, at the conclusion of stage 5, at the beginning of stage 6, etc. Examples of methods of making cells of any one of stages 1-6 are provided in, for example, US Patent 10,030,229; US Patent 10,443,042; published application US 20200332262; and published application US 20210198632, published application US 20220090020, and published application WO2022147056, each of which is incorporated by reference in its entirety. Compositions and methods for producing pancreatic islet cells In aspects, the present disclosure provides compositions and methods of differentiating pancreatic islet cells (e.g., differentiating from stem cells such as human embryonic stem cells or human pluripotent stem cells). The compositions and methods provided herein can, in some embodiments, offer pancreatic SC-islet cells, cell populations, or cell clusters containing pancreatic SC-P cells and pancreatic SC-a cells. In some embodiments, such pancreatic SC-islet cells, cell populations or cell clusters exhibit, high insulin content, superior glucose-dependent insulin secretion response, as well as a percentage of pancreatic SC-a, SC-P, and SC-6 cells and enterochromaffin (EC) cells, which can resemble native pancreatic islets both structurally and functionally. In some embodiments, a population of pancreatic islet cells (e.g., stem cell derived pancreatic islet cells) produced using the compositions and methods described herein comprises about 30%-45% pancreatic SC-P cells, 40%-50% pancreatic a cells, 3-10% pancreatic SC-6 cells, and / or less than 20% SC-EC cells. In some embodiments, a population of pancreatic islet cells (e.g., stem cell derived pancreatic islet cells) produced using the compositions and methods described herein has improved glucose-stimulated insulin secretion (GSIS) response as compared to cell compositions generated according to conventional methods. In some embodiments, a population of pancreatic islet cells (e.g., stem cell derived pancreatic islet cells) produced using the compositions and methods described herein has dynamic GSIS response similar to native pancreatic islets (e.g., pancreatic islets from a healthy functioning pancreas from a healthy adult non-diabetic subject). In some embodiments, a method of producing pancreatic islet cells (e.g., SC-beta cells, SC-alpha cells, SC-delta cells) described herein comprises contacting pancreatic progenitor cells (e.g., pancreatic progenitor cells that are PDXl-positive and NKX6.1-negative) with a medium comprising a comprising a Forkhead Box 01 (FoxOl) inhibitor and / or a notch signaling pathway inhibitor (e.g., a y-secretase inhibitor). In some embodiments, a method described herein comprises contacting pancreatic progenitor cells in a culture with a FOXO1 inhibitor and / or a notch signaling pathway inhibitor (e.g., a y-secretase inhibitor), wherein the culture comprises pancreatic progenitor cells that are PDXl-positive and NKX6.1-negative and pancreatic progenitor cells that are PDXl-positive and NKX6.1-positive. In some embodiments, a method described herein comprises contacting pancreatic progenitor cells (e.g., pancreatic progenitor cells that are PDXl-positive and NKX6.1-positive) with a medium comprising a comprising a Wnt signaling pathway inhibitor and / or a PKC activator. In some embodiments, a method described herein comprises contacting pancreatic progenitor cells (e.g., pancreatic progenitor cells that are PDXl-positive and NKX6.1-negative) with a medium comprising a comprising a Forkhead Box 01 (FoxOl) inhibitor and / or a notch signaling pathway inhibitor (e.g., a y-secretase inhibitor), and contacting resulting cells with a medium comprising a comprising a Wnt signaling pathway inhibitor and / or a PKC activator. In some embodiments, the method does not comprise the step of contacting cells with a Wnt signaling pathway inhibitor and a FoxOl inhibitor at the same time. Composition comprising FoxOl inhibitor and optionally a Notch signaling inhibitor In some aspects, the present disclosure provides in vitro compositions comprising a population of pancreatic progenitor cells and a medium comprising a Forkhead Box 01 (FoxOl) inhibitor. In some embodiments, the medium further comprises a notch signaling pathway inhibitor (e.g., a y-secretase inhibitor). In some embodiments, the medium further comprises a PKC activator. In some embodiments, the medium further comprises one or more (e.g., 1, 2, 3, 4, 5) agents selected from: a fibroblast growth factor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, and a TGF-P ligand. In some embodiments, the medium further comprises a fibroblast growth factor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, and a TGF-P ligand. In some embodiments, the medium comprises a FoxOl inhibitor, a notch signaling pathway inhibitor (e.g., a y-secretase inhibitor), a PKC activator, a fibroblast growth factor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, and a TGF-P ligand. In some embodiments, the medium comprises FoxOl inhibitor AS 1842856 (e.g., Catalog #344355 as Sigma-Aldrich), XXI, PdBu, keratinocyte growth factor (KGF), SANT-1, RA, triazovivin, and activin A. In some embodiments, the medium does not comprise a Wnt signaling pathway inhibitor. In some embodiments, a FoxOl inhibitor (e.g., AS 1842856) is present in the medium at a concentration of 0.1 pM-10 pM. In some embodiments, a FoxOl inhibitor (AS 1842856) is present in the medium at a concentration of 0.1 pM-10 pM, 0.1 pM-9 pM, 0.1 pM-8 pM, 0.1 pM-7 pM, 0.1 pM-6 pM, 0.1 pM-5 pM, 0.1 pM-4 pM, 0.1 pM-3 pM, 0.1 pM-2 pM, 0.1 pM-1 pM, 0.1 pM-0.5 pM, 0.5 pM-10 pM, 0.5 pM-9 pM, 0.5 pM-8 pM, 0.5 pM-7 pM, 0.5 pM-6 pM, 0.5 pM-5 pM, 0.5 pM-4 pM, 0.5 pM-3 pM, 0.5 pM-2 pM, 0.5 pM-1 pM, 1 pM-10 pM, 1 pM-9 pM, 1 pM-8 pM, 1 pM-7 pM, 1 pM-6 pM, 1 pM-5 pM, 1 pM-4 pM, 1 pM-3 pM, 1 pM-2 pM, 2 pM-10 pM, 2 pM-9 pM, 2 pM-8 pM, 2 pM-7 pM, 2 pM-6 pM, 2 pM-5 pM, 2 pM-4 pM, 2 pM-3 pM, 3 pM-10 pM, 3 pM-9 pM, 3 pM-8 pM, 3 pM-7 pM, 3 pM-6 pM, 3 pM-5 pM, 3 pM-4 pM, 4 pM-10 pM, 4 pM-9 pM, 4 pM-8 pM, 4 pM-7 pM, 4 pM-6 pM, 4 pM-5 pM, 5 pM-10 pM, 5 pM-9 pM, 5 pM-8 pM, 5 pM-7 pM, 5 pM-6 pM, 6 pM-10 pM, 6 pM-9 pM, 6 pM-8 pM, 6 pM-7 pM, 7 pM-10 pM, 7 pM-9 pM, 7 pM-8 pM, 8 pM-10 pM, 8 pM-9 pM, or 9 pM-10 pM. In some embodiments, a FoxOl inhibitor (e.g., AS 1842856) is present in the medium at a concentration of 0.5 pM-5 pM (e.g., 0.5 pM, 1 pM, 1.5 pM, 2 pM, 2.5 pM, 3 pM, 3.5 pM, 4 pM, 4.5 pM, or 5 pM). In some embodiments, a FoxOl inhibitor (e.g., AS 1842856) is present in the medium at a concentration of 0.7-1.3 pM, 0.8-1.2 pM, or 0.9-1.1 pM. In some embodiments, a FoxOl inhibitor (e.g., AS 1842856) is present in the medium at a concentration of 1 pM. In some embodiments, a notch signaling pathway inhibitor (e.g., y-secretase inhibitor such as XXI) is present in the medium at a concentration of 0.1 pM-10 pM. In some embodiments, a notch signaling pathway inhibitor (e.g., y-secretase inhibitor such as XXI) is present in the medium at a concentration of 0.1 pM-10 pM, 0.1 pM-9 pM, 0.1 pM-8 pM, 0.1 pM-7 pM, 0.1 pM-6 pM, 0.1 pM-5 pM, 0.1 pM-4 pM, 0.1 pM-3 pM, 0.1 pM-2 pM, 0.1 pM-1 pM, 0.1 pM-0.5 pM, 0.5 pM-10 pM, 0.5 pM-9 pM, 0.5 pM-8 pM, 0.5 pM-7 pM, 0.5 pM-6 pM, 0.5 pM-5 pM, 0.5 pM-4 pM, 0.5 pM-3 pM, 0.5 pM-2 pM, 0.5 pM-1 pM, 1 pM-10 pM, 1 pM-9 pM, 1 pM-8 pM, 1 pM-7 pM, 1 pM-6 pM, 1 pM-5 pM, 1 pM-4 pM, 1 pM-3 pM, 1 pM-2 pM, 2 pM-10 pM, 2 pM-9 pM, 2 pM-8 pM, 2 pM-7 pM, 2 pM-6 pM, 2 pM-5 pM, 2 pM-4 pM, 2 pM-3 pM, 3 pM-10 pM, 3 pM-9 pM, 3 pM-8 pM, 3 pM-7 pM, 3 pM-6 pM, 3 pM-5 pM, 3 pM-4 pM, 4 pM-10 pM, 4 pM-9 pM, 4 pM-8 pM, 4 pM-7 pM, 4 pM-6 pM, 4 pM-5 pM, 5 pM-10 pM, 5 pM-9 pM, 5 pM-8 pM, 5 pM-7 pM, 5 pM-6 pM, 6 pM-10 pM, 6 pM-9 pM, 6 pM-8 pM, 6 pM-7 pM, 7 pM-10 pM, 7 pM-9 pM, 7 pM-8 pM, 8 pM-10 pM, 8 pM-9 pM, or 9 pM-10 pM. In some embodiments, a notch signaling pathway inhibitor (e.g., y-secretase inhibitor such as XXI) is present in the medium at a concentration of 0.5 pM-5 pM (e.g., 0.5 pM, 1 pM, 1.5 pM, 2 pM, 2.5 pM, 3 pM, 3.5 pM, 4 pM, 4.5 pM, or 5 pM). In some embodiments, a notch signaling pathway inhibitor (e.g., y-secretase inhibitor such as XXI) is present in the medium at a concentration of 1.5 pM-2.5 pM or 1.8 pM-2.2 pM. In some embodiments, a notch signaling pathway inhibitor (e.g., y-secretase inhibitor such as XXI) is present in the medium at a concentration of 2 pM. In some embodiments, a PKC activator (e.g., PdBu) is present in the medium at a concentration of 0.1 pM-10 pM. In some embodiments, a PKC activator (e.g., PdBu) is present in the medium at a concentration of 0.1 pM-10 pM, 0.1 pM-9 pM, 0.1 pM-8 pM, 0.1 pM-7 pM, 0.1 pM-6 pM, 0.1 pM-5 pM, 0.1 pM-4 pM, 0.1 pM-3 pM, 0.1 pM-2 pM, 0.1 pM-1 pM, 0.1 pM-0.5 pM, 0.5 pM-10 pM, 0.5 pM-9 pM, 0.5 pM-8 pM, 0.5 pM-7 pM, 0.5 pM-6 pM, 0.5 pM-5 pM, 0.5 pM-4 pM, 0.5 pM-3 pM, 0.5 pM-2 pM, 0.5 pM-1 pM, 1 pM-10 pM, 1 pM-9 pM, 1 pM-8 pM, 1 pM-7 pM, 1 pM-6 pM, 1 pM-5 pM, 1 pM-4 pM, 1 pM-3 pM, 1 pM-2 pM, 2 pM-10 pM, 2 pM-9 pM, 2 pM-8 pM, 2 pM-7 pM, 2 pM-6 pM, 2 pM-5 pM, 2 pM-4 pM, 2 pM-3 pM, 3 pM-10 pM, 3 pM-9 pM, 3 pM-8 pM, 3 pM-7 pM, 3 pM-6 pM, 3 pM-5 pM, 3 pM-4 pM, 4 pM-10 pM, 4 pM-9 pM, 4 pM-8 pM, 4 pM-7 pM, 4 pM-6 pM, 4 pM-5 pM, 5 pM-10 pM, 5 pM-9 pM, 5 pM-8 pM, 5 pM-7 pM, 5 pM-6 pM, 6 pM-10 pM, 6 pM-9 pM, 6 pM-8 pM, 6 pM-7 pM, 7 pM-10 pM, 7 pM-9 pM, 7 pM-8 pM, 8 pM-10 pM, 8 pM-9 pM, or 9 pM-10 pM. In some embodiments, a PKC activator (e.g., PdBu) is present in the medium at a concentration of 0.2 pM-1 pM (e.g., 0.2 pM, 0.3 pM, 0.4 pM, 0.5 pM, 0.6 pM , 0.7 pM, 0.8 pM, 0.9 pM, or 1 pM). In some embodiments, a PKC activator (e.g., PdBu) is present in the medium at a concentration of 0.3 pM-0.7 pM or 0.4 pM-0.6 pM. In some embodiments, a PKC activator (e.g., PdBu) is present in the medium at a concentration of 0.5 pM. In some embodiments, a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1) is present in the medium at a concentration of 0.1 pM-10 pM. In some embodiments, a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1) is present in the medium at a concentration of 0.1 pM-10 pM, 0.1 pM-9 pM, 0.1 pM-8 pM, 0.1 pM-7 pM, 0.1 pM-6 pM, 0.1 pM-5 pM, 0.1 pM-4 pM, 0.1 pM-3 pM, 0.1 pM-2 pM, 0.1 pM-1 pM, 0.1 pM-0.5 pM, 0.5 pM-10 pM, 0.5 pM-9 pM, 0.5 pM-8 pM, 0.5 pM-7 pM, 0.5 pM-6 pM, 0.5 pM-5 pM, 0.5 pM-4 pM, 0.5 pM-3 pM, 0.5 pM-2 pM, 0.5 pM-1 pM, 1 pM-10 pM, 1 pM-9 pM, 1 pM-8 pM, 1 pM-7 pM, 1 pM-6 pM, 1 pM-5 pM, 1 pM-4 pM, 1 pM-3 pM, 1 pM-2 pM, 2 pM-10 pM, 2 pM-9 pM, 2 pM-8 pM, 2 pM-7 pM, 2 pM-6 pM, 2 pM-5 pM, 2 pM-4 pM, 2 pM-3 pM, 3 pM-10 pM, 3 pM-9 pM, 3 pM-8 pM, 3 pM-7 pM, 3 pM-6 pM, 3 pM-5 pM, 3 pM-4 pM, 4 pM-10 pM, 4 pM-9 pM, 4 pM-8 pM, 4 pM-7 pM, 4 pM-6 pM, 4 pM-5 pM, 5 pM-10 pM, 5 pM-9 pM, 5 pM-8 pM, 5 pM-7 pM, 5 pM-6 pM, 6 pM-10 pM, 6 pM-9 pM, 6 pM-8 pM, 6 pM-7 pM, 7 pM-10 pM, 7 pM-9 pM, 7 pM-8 pM, 8 pM-10 pM, 8 pM-9 pM, or 9 pM-10 pM. In some embodiments, a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1) is present in the medium at a concentration of 0.1 pM-0.5 pM (e.g., 0.1 pM, 0.15 pM, 0.2 pM, 0.25 pM, 0.3 pM, 0.35 pM, 0.4 pM, 0.45 pM, or 0.5 pM). In some embodiments, a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1) is present in the medium at a concentration of 0.25 pM. In some embodiments, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., thiazovivin) is present in the medium at a concentration of 1 pM-10 pM. In some embodiments, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., thiazovivin) is present in the medium at a concentration of 1 pM-10 pM, 1 pM-9 pM, 1 pM-8 pM, 1 pM-7 pM, 1 pM-6 pM, 1 pM-5 pM, 1 pM-4 pM, 1 pM-3 pM, 1 pM-2 pM, 2 pM-10 pM, 2 pM-9 pM, 2 pM-8 pM, 2 pM-7 pM, 2 pM-6 pM, 2 pM-5 pM, 2 pM-4 pM, 2 pM-3 pM, 3 pM-10 pM, 3 pM-9 pM, 3 pM-8 pM, 3 pM-7 pM, 3 pM-6 pM, 3 pM-5 pM, 3 pM-4 pM, 4 pM-10 pM, 4 pM-9 pM, 4 pM-8 pM, 4 pM-7 pM, 4 pM-6 pM, 4 pM-5 pM, 5 pM-10 pM, 5 pM-9 pM, 5 pM-8 pM, 5 pM-7 pM, 5 pM-6 pM, 6 pM-10 pM, 6 pM-9 pM, 6 pM-8 pM, 6 pM-7 pM, 7 pM-10 pM, 7 pM-9 pM, 7 pM-8 pM, 8 pM-10 pM, 8 pM-9 pM, or 9 pM-10 pM. In some embodiments, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., thiazovivin) is present in the medium at a concentration of 1 pM- 5 pM (e.g., 1 pM, 1.5 pM, 2 pM, 2.5 pM, 3 pM, 3.5 pM, 4 pM, 4.5 pM, or 5 pM). In some embodiments, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., thiazovivin) is present in the medium at a concentration of 2.5 pM. In some embodiments, retinoic acid is present in the medium at a concentration of 0.05 pM-0.5 pM. In some embodiments, retinoic acid is present in the medium at a concentration of 0.05 pM-0.5 pM, 0.1 pM-0.5 pM, 0.15 pM-0.5 pM, 0.2 pM-0.5 pM, 0.25 pM-0.5 pM, 0.3 pM-0.5 pM, 0.35 pM-0.5 pM, 0.4 pM-0.5 pM, 0.45 pM-0.5 pM, 0.05 pM-0.4 pM, 0.1 pM-0.4 pM, 0.15 pM-0.4 pM, 0.2 pM-0.4 pM, 0.25 pM-0.4 pM, 0.3 pM-0.4 pM, 0.35 pM-0.4 pM, 0.05 pM-0.3 pM, 0.1 pM-0.3 pM, 0.15 pM-0.3 pM, 0.2 pM-0.3 pM, 0.25 pM-0.3 pM, 0.05 pM-0.2 pM, 0.1 pM-0.2 pM, 0.15 pM-0.2 pM, or 0.05 pM-0.1 pM. In some embodiments, retinoic acid is present in the medium at a concentration of 0.05 pM-0.2 pM (e.g., 0.05 pM, 0.1 pM, 0.15 pM, or 0.2 pM). In some embodiments, retinoic acid is present in the medium at a concentration of 0.1 pM. In some embodiments, a TGF-P ligand (e.g., activin A) is present in the medium at a concentration of 1 ng / ml-10 ng / ml. In some embodiments, a TGF-P ligand (e.g., activin A) is present in the medium at a concentration of 1 ng / ml-10 ng / ml, 1 ng / ml-9 ng / ml, 1 ng / ml-8 ng / ml, 1 ng / ml-7 ng / ml, 1 ng / ml-6 ng / ml, 1 ng / ml-5 ng / ml, 1 ng / ml-4 ng / ml, 1 ng / ml-3 ng / ml, 1 ng / ml-2 ng / ml, 2 ng / ml-10 ng / ml, 2 ng / ml-9 ng / ml, 2 ng / ml-8 ng / ml, 2 ng / ml-7 ng / ml, 2 ng / ml-6 ng / ml, 2 ng / ml-5 ng / ml, 2 ng / ml-4 ng / ml, 2 ng / ml-3 ng / ml, 3 ng / ml-10 ng / ml, 3 ng / ml-9 ng / ml, 3 ng / ml-8 ng / ml, 3 ng / ml-7 ng / ml, 3 ng / ml-6 ng / ml, 3 ng / ml-5 ng / ml, 3 ng / ml-4 ng / ml, 4 ng / ml-10 ng / ml, 4 ng / ml-9 ng / ml, 4 ng / ml-8 ng / ml, 4 ng / ml-7 ng / ml, 4 ng / ml-6 ng / ml, 4 ng / ml-5 ng / ml, 5 ng / ml-10 ng / ml, 5 ng / ml-9 ng / ml, 5 ng / ml-8 ng / ml, 5 ng / ml-7 ng / ml, 5 ng / ml-6 ng / ml, 6 ng / ml-10 ng / ml, 6 ng / ml-9 ng / ml, 6 ng / ml-8 ng / ml, 6 ng / ml-7 ng / ml, 7 ng / ml-10 ng / ml, 7 ng / ml-9 ng / ml, 7 ng / ml-8 ng / ml, 8 ng / ml-10 ng / ml, 8 ng / ml-9 ng / ml, or 9 ng / ml-10 ng / ml. In some embodiments, a TGF-P ligand (e.g., activin A) is present in the medium at a concentration of 2 ng / ml-8 ng / ml (e.g., 2 ng / ml, 3 ng / ml, 4 ng / ml, 5 ng / ml, 6 ng / ml, 7 ng / ml, 8 ng / ml). In some embodiments, a TGF-P ligand (e.g., activin A) is present in the medium at a concentration of 5 ng / ml. In some embodiments, a fibroblast growth factor (e.g., keratinocyte growth factor (KGF)) is present in the medium at a concentration of 10 ng / ml-100 ng / ml. In some embodiments, a fibroblast growth factor (e.g., keratinocyte growth factor (KGF)) is present in the medium at a concentration of 10 ng / ml-100 ng / ml, 10 ng / ml-90 ng / ml, 10 ng / ml-80 ng / ml, 10 ng / ml-70 ng / ml, 10 ng / ml-60 ng / ml, 10 ng / ml-50 ng / ml, 10 ng / ml-40 ng / ml, 10 ng / ml-30 ng / ml, 10 ng / ml-20 ng / ml, 20 ng / ml-100 ng / ml, 20 ng / ml-90 ng / ml, 20 ng / ml-80 ng / ml, 20 ng / ml-70 ng / ml, 20 ng / ml-60 ng / ml, 20 ng / ml-50 ng / ml, 20 ng / ml-40 ng / ml, 20 ng / ml-30 ng / ml, 30 ng / ml-100 ng / ml, 30 ng / ml-90 ng / ml, 30 ng / ml-80 ng / ml, 30 ng / ml-70 ng / ml, 30 ng / ml-60 ng / ml, 30 ng / ml-50 ng / ml, 30 ng / ml-40 ng / ml, 40 ng / ml-100 ng / ml, 40 ng / ml-90 ng / ml, 40 ng / ml-80 ng / ml, 40 ng / ml-70 ng / ml, 40 ng / ml-60 ng / ml, 40 ng / ml-50 ng / ml, 50 ng / ml-100 ng / ml, 50 ng / ml-90 ng / ml, 50 ng / ml-80 ng / ml, 50 ng / ml-70 ng / ml, 50 ng / ml-60 ng / ml, 60 ng / ml-100 ng / ml, 60 ng / ml-90 ng / ml, 60 ng / ml-80 ng / ml, 60 ng / ml-70 ng / ml, 70 ng / ml-100 ng / ml, 70 ng / ml-90 ng / ml, 70 ng / ml-80 ng / ml, 80 ng / ml-100 ng / ml, 80 ng / ml-90 ng / ml, or 90 ng / ml-100 ng / ml. In some embodiments, a fibroblast growth factor (e.g., keratinocyte growth factor (KGF)) is present in the medium at a concentration of 20 ng / ml-80 ng / ml (e.g., 20 ng / ml, 30 ng / ml, 40 ng / ml, 50 ng / ml, 60 ng / ml, 70 ng / ml, 80 ng / ml). In some embodiments, a fibroblast growth factor (e.g., keratinocyte growth factor (KGF)) is present in the medium at a concentration of 50 ng / ml. In some embodiments, the medium comprises a FoxOl inhibitor (e.g., AS 1842856) at a concentration of 0.5 pM-5 pM, a notch signaling pathway inhibitor (e.g., a y-secretase inhibitor such as XXI) at a concentration of 0.5 pM-5 pM, a PKC activator (e.g., PdBu) at a concentration of 0.2 pM-1 pM, a fibroblast growth factor (e.g., KGF) at a concentration of 20 ng / ml-80 ng / ml, a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1) at a concentration of 0.1 pM-0.5 pM, retinoic acid at a concentration of 0.05 pM-0.2 pM, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., thiazovivin) at a concentration of 1 pM- 5 pM, and a TGF-P ligand (e.g., activin A) at a concentration of 2 ng / ml-8 ng / ml. In some embodiments, the medium comprises a FoxOl inhibitor (e.g., AS 1842856) at a concentration of 1 pM, a notch signaling pathway inhibitor (e.g., a y-secretase inhibitor such as XXI) at a concentration of 2 pM, a PKC activator (e.g., PdBu) at a concentration of 0.5 pM, a fibroblast growth factor (e.g., KGF) at a concentration of 50 ng / ml, a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1) at a concentration of 0.25 pM, retinoic acid at a concentration of 0.1 pM, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., thiazovivin) at a concentration of 2.5 pM, and a TGF-P ligand (e.g., activin A) at a concentration of 5 ng / ml. In some embodiments, an in vitro composition described herein further comprises a water-soluble synthetic polymer. In some embodiments, the water-soluble synthetic polymer is polyvinyl alcohol (PVA), poloxamer, polyvinylpyrrolidone, polyethylene glycol (PEG), PEG copolymers, poly(N-isopropylacrylamide), or polyacrylamide, optionally wherein the watersoluble synthetic polymer is polyvinyl alcohol. In some embodiments, the water water-soluble synthetic polymer is polyvinyl alcohol (PVA). In some embodiments, the water-soluble synthetic polymer has a concentration of 0.005% to 0.5% (w / v), 0.01% to 0.2% (w / v), 0.02% to 0.1% (w / v), or 0.03% to 0.08% (w / v) of the culture medium. In some embodiments, the watersoluble synthetic polymer has a concentration of 0.005% (w / v), 0.01% (w / v), 0.05% (w / v), 0.1% (w / v), 0.15% (w / v), 0.2% (w / v), 0.25% (w / v), 0.3% (w / v), 0.35% (w / v), to 0.4% (w / v), 0.45% (w / v), or 0.5% (w / v) of the medium. In some embodiments, the water-soluble synthetic polymer is polyvinyl alcohol (PVA), and the PVA is at most 85% (e.g., 75%-80%) hydrolyzed. In some embodiments, an in vitro composition comprises a population of pancreatic progenitor cells comprising cells that are PDXl-positive and NKX6.1-negative. In some embodiments, an in vitro composition comprising described herein comprises a population of pancreatic progenitor cells comprising cells that are PDXl-positive and NKX6.1-positive. In some embodiments, an in vitro composition comprising described herein comprises a population of pancreatic progenitor cells comprising cells that are PDXl-positive and NKX6.1-negative and cells that are PDXl-positive and NKX6.1-positive. In some embodiments, the PDXl-positive and NKX6.1-positive cells are insulin-negative. In some embodiments, the population of pancreatic progenitor cells comprises more cells that are PDXl-positive and NKX6.1-negative than cells that are PDXl-positive and NKX6.1-positive. In some embodiments, at least 50% (e.g., at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%) of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-negative. In some embodiments, no more than 50% (e.g., no more than 50%, no more than 40%, no more than 30%, no more than 20%, or no more than 10%) of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDXl-positive and NKX6.1-positive. In some embodiments, 50%-90% (e.g., 50%-90%, 50%-80%, 50%-70%, 50%-60%, 60%-90%, 60%-80%, 60%-70%, 30%-80%, 70%-90%, 70%-80%, or 80%-90%) of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-negative. In some embodiments, 10%-50% (e.g., 10%-50%, 20%-50%, 30%-50%, 40%-50%, 10%-40%, 20%-40%, 30%-40%, 10%-30%, 20%-30%, or 10%-20%,) of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDXl-positive and NKX6.1-positive. In some embodiments, 50%-90% (e.g., 50%-90%, 50%-80%, 50%-70%, 50%-60%, 60%-90%, 60%-80%, 60%-70%, 30%-80%, 70%-90%, 70%-80%, or 80%-90%) of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-negative and 10%-50% (e.g., 10%-50%, 20%-50%, 30%-50%, 40%-50%, 10%-40%, 20%-40%, 30%-40%, 10%-30%, 20%-30%, or 10%- 20%,) of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDXl-positive and NKX6.1-positive. In some embodiments, at least 50% of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-negative, and no more than 50% of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDXl-positive and NKX6.1-positive. In some embodiments, the population of pancreatic progenitor cells comprises more cells that are PDXl-positive and NKX6.1-positive than cells that are PDXl-positive and NKX6.1-negative. In some embodiments, at least 50% (e.g., at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%) of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-positive. In some embodiments, no more than 50% (e.g., no more than 50%, no more than 40%, no more than 30%, no more than 20%, or no more than 10%) of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDXl-positive and NKX6.1-negative. In some embodiments, 50%-90% (e.g., 50%-90%, 50%-80%, 50%-70%, 50%-60%, 60%-90%, 60%-80%, 60%-70%, 30%-80%, 70%-90%, 70%-80%, or 80%-90%) of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-positive. In some embodiments, 10%-50% (e.g., 10%-50%, 20%-50%, 30%-50%, 40%-50%, 10%-40%, 20%-40%, 30%-40%, 10%-30%, 20%-30%, or 10%-20%,) of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDXl-positive and NKX6.1-negative. In some embodiments, 50%-90% (e.g., 50%-90%, 50%-80%, 50%-70%, 50%-60%, 60%-90%, 60%-80%, 60%-70%, 30%-80%, 70%-90%, 70%-80%, or 80%-90%) of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-positive and 10%-50% (e.g., 10%-50%, 20%-50%, 30%-50%, 40%-50%, 10%-40%, 20%-40%, 30%-40%, 10%-30%, 20%-30%, or 10%-20%,) of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDXl-positive and NKX6.1-negative. In some embodiments, at least 50% of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-positive, and no more than 50% of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDXl-positive and NKX6.1-negative. Composition comprising Wnt inhibitor and optionally a PKC activator The present disclosure, in other aspects, provides in vitro compositions comprising a population of pancreatic progenitor cells comprising cells that are PDXl-positive, NKX6.1-positive, and insulin-negative; and a medium comprising a Wnt signaling pathway inhibitor (e.g., a tankyrase inhibitor). In some embodiments, the medium further comprises a protein kinase C (PKC) activator. In some embodiments, the medium does not comprise a FOXO1 inhibitor. In some embodiments, the population of pancreatic progenitor cells had been previously cultured in a medium comprising a FOXO1 inhibitor. In some embodiments, the medium further comprises 37 one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) agents selected from: a sonic hedgehog (SHH) signaling pathway inhibitor, an epidermal growth factor, a notch signaling pathway inhibitor (e.g., a y-secretase inhibitor), a TGFP-R1 kinase inhibitor, a thyroid hormone, a bone morphogenetic (BMP) signaling pathway inhibitor, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a histone methyltransferase EZH2 inhibitor, and retinoic acid. In some embodiments, the medium further comprises a sonic hedgehog (SHH) signaling pathway inhibitor, an epidermal growth factor, a notch signaling pathway inhibitor (e.g., a y-secretase inhibitor), a TGF0-R1 kinase inhibitor, a thyroid hormone, a bone morphogenetic (BMP) signaling pathway inhibitor, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a histone methyltransferase EZH2 inhibitor, and retinoic acid. In some embodiments, the medium further comprises one or more (e.g., 1, 2, 3, or 4) agents selected from an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, and a one carbon metabolism pathway intermediate. In some embodiments, the medium further comprises acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, and a one carbon metabolism pathway intermediate. In some embodiments, the medium further comprises a vitamin. In some embodiments, the medium further comprises glutamine. In some embodiments, the medium comprises a PKC activator, Wnt signaling pathway inhibitor (e.g., a tankyrase inhibitor), a sonic hedgehog (SHH) signaling pathway inhibitor, an epidermal growth factor, a notch signaling pathway inhibitor (e.g., a y-secretase inhibitor), a TGFP-R1 kinase inhibitor, a thyroid hormone, a bone morphogenetic (BMP) signaling pathway inhibitor, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a histone methyltransferase EZH2 inhibitor, retinoic acid, an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, a one carbon metabolism pathway intermediate, a vitamin, and glutamine. In some embodiments, the medium comprises PdBu, NVP-TNKS656, SANT-1, betacellulin, XXI, Alk5i, GC-1, LDN-193189, thiazovivin, staurosporine, DZNEP, retinoic acid, acetate, P-hydroxybutyrate, taurine, formate, biotin, and glutamine. In some embodiments, a PKC activator (e.g., PdBu) is present in the medium at a concentration of 0.1 pM-10 pM. In some embodiments, a PKC activator (e.g., PdBu) is present in the medium at a concentration of 0.1 pM-10 pM, 0.1 pM-9 pM, 0.1 pM-8 pM, 0.1 pM-7 pM, 0.1 pM-6 pM, 0.1 pM-5 pM, 0.1 pM-4 pM, 0.1 pM-3 pM, 0.1 pM-2 pM, 0.1 pM-1 pM, 0.1 pM-0.5 pM, 0.5 pM-10 pM, 0.5 pM-9 pM, 0.5 pM-8 pM, 0.5 pM-7 pM, 0.5 pM-6 pM, 0.5 pM-5 pM, 0.5 pM-4 pM, 0.5 pM-3 pM, 0.5 pM-2 pM, 0.5 pM-1 pM, 1 pM-10 pM, 1 pM-9 pM, 1 pM-8 pM, 1 pM-7 pM, 1 pM-6 pM, 1 pM-5 pM, 1 pM-4 pM, 1 pM-3 pM, 1 pM-2 pM, 2 pM-10 pM, 2 pM-9 pM, 2 pM-8 pM, 2 pM-7 pM, 2 pM-6 pM, 2 pM-5 pM, 2 pM-4 pM, 2 pM-3 pM, 3 pM-10 pM, 3 pM-9 pM, 3 pM-8 pM, 3 pM-7 pM, 3 pM-6 pM, 3 pM-5 pM, 3 pM-4 pM, 4 pM-10 pM, 4 pM-9 pM, 4 pM-8 pM, 4 pM-7 pM, 4 pM-6 pM, 4 pM-5 pM, 5 pM-10 pM, 5 pM-9 pM, 5 pM-8 pM, 5 pM-7 pM, 5 pM-6 pM, 6 pM-10 pM, 6 pM-9 pM, 6 pM-8 pM, 6 pM-7 pM, 7 pM-10 pM, 7 pM-9 pM, 7 pM-8 pM, 8 pM-10 pM, 8 pM-9 pM, or 9 pM-10 pM. In some embodiments, a PKC activator (e.g., PdBu) is present in the medium at a concentration of 0.2 pM-1 pM (e.g., 0.2 pM, 0.3 pM, 0.4 pM, 0.5 pM, 0.6 pM , 0.7 pM, 0.8 pM, 0.9 pM, or 1 pM). In some embodiments, a PKC activator (e.g., PdBu) is present in the medium at a concentration of 0.3 pM-0.7 pM or 0.4 pM-0.6 pM. In some embodiments, a PKC activator (e.g., PdBu) is present in the medium at a concentration of 0.5 pM. In some embodiments, a Wnt signaling pathway inhibitor (e.g., a tankyrase inhibitor such as NVP-TNKS656) is present in the medium at a concentration of 0.1 pM-10 pM. In some embodiments, a Wnt signaling pathway inhibitor (e.g., a tankyrase inhibitor such as NVP-TNKS656) is present in the medium at a concentration of 0.1 pM-10 pM, 0.1 pM-9 pM, 0.1 pM-8 pM, 0.1 pM-7 pM, 0.1 pM-6 pM, 0.1 pM-5 pM, 0.1 pM-4 pM, 0.1 pM-3 pM, 0.1 pM-2 pM, 0.1 pM-1 pM, 0.1 pM-0.5 pM, 0.1 pM-0.2 pM, 0.2 pM-10 pM, 0.2 pM-9 pM, 0.2 pM-8 pM, 0.2 pM-7 pM, 0.2 pM-6 pM, 0.2 pM-5 pM, 0.2 pM-4 pM, 0.2 pM-3 pM, 0.2 pM-2 pM, 0.2 pM-1 pM, 0.2 pM-0.5 pM, 0.5 pM-10 pM, 0.5 pM-9 pM, 0.5 pM-8 pM, 0.5 pM-7 pM, 0.5 pM-6 pM, 0.5 pM-5 pM, 0.5 pM-4 pM, 0.5 pM-3 pM, 0.5 pM-2 pM, 0.5 pM-1 pM, 1 pM-10 pM, 1 pM-9 pM, 1 pM-8 pM, 1 pM-7 pM, 1 pM-6 pM, 1 pM-5 pM, 1 pM-4 pM, 1 pM-3 pM, 1 pM-2 pM, 2 pM-10 pM, 2 pM-9 pM, 2 pM-8 pM, 2 pM-7 pM, 2 pM-6 pM, 2 pM-5 pM, 2 pM-4 pM, 2 pM-3 pM, 3 pM-10 pM, 3 pM-9 pM, 3 pM-8 pM, 3 pM-7 pM, 3 pM-6 pM, 3 pM-5 pM, 3 pM-4 pM, 4 pM-10 pM, 4 pM-9 pM, 4 pM-8 pM, 4 pM-7 pM, 4 pM-6 pM, 4 pM-5 pM, 5 pM-10 pM, 5 pM-9 pM, 5 pM-8 pM, 5 pM-7 pM, 5 pM-6 pM, 6 pM-10 pM, 6 pM-9 pM, 6 pM-8 pM, 6 pM-7 pM, 7 pM-10 pM, 7 pM-9 pM, 7 pM-8 pM, 8 pM-10 pM, 8 pM-9 pM, or 9 pM-10 pM. In some embodiments, a Wnt signaling pathway inhibitor (e.g., a tankyrase inhibitor such as NVP-TNKS656) is present in the medium at a concentration of 0.5 pM-5 pM (e.g., 0.5 pM, 1 pM, 1.5 pM, 2 pM, 2.5 pM, 3 pM, 3.5 pM, 4 pM, 4.5 pM, or 5 pM). In some embodiments, a Wnt signaling pathway inhibitor (e.g., a tankyrase inhibitor such as NVP-TNKS656) is present in the medium at a concentration of 1.5 pM-2.5 pM or 1.8 pM-2.2 pM. In some embodiments, a Wnt signaling pathway inhibitor (e.g., a tankyrase inhibitor such as NVP-TNKS656) is present in the medium at a concentration of 2 pM. In some embodiments, a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1) is present in the medium at a concentration of 0.1 pM-10 pM. In some embodiments, a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1) is present in the medium at a concentration of 0.1 pM-10 pM, 0.1 pM-9 pM, 0.1 pM-8 pM, 0.1 pM-7 pM, 0.1 pM-6 pM, 0.1 pM-5 pM, 0.1 pM-4 pM, 0.1 pM-3 pM, 0.1 pM-2 pM, 0.1 pM-1 pM, 0.1 pM-0.5 pM, 0.5 pM-10 pM, 0.5 pM-9 pM, 0.5 pM-8 pM, 0.5 pM-7 pM, 0.5 pM-6 pM, 0.5 pM-5 pM, 0.5 pM-4 pM, 0.5 pM-3 pM, 0.5 pM-2 pM, 0.5 pM-1 pM, 1 pM-10 pM, 1 pM-9 pM, 1 pM-8 pM, 1 pM-7 pM, 1 pM-6 pM, 1 pM-5 pM, 1 pM-4 pM, 1 pM-3 pM, 1 pM-2 pM, 2 pM-10 pM, 2 pM-9 pM, 2 pM-8 pM, 2 pM-7 pM, 2 pM-6 pM, 2 pM-5 pM, 2 pM-4 pM, 2 pM-3 pM, 3 pM-10 pM, 3 pM-9 pM, 3 pM-8 pM, 3 pM-7 pM, 3 pM-6 pM, 3 pM-5 pM, 3 pM-4 pM, 4 pM-10 pM, 4 pM-9 pM, 4 pM-8 pM, 4 pM-7 pM, 4 pM-6 pM, 4 pM-5 pM, 5 pM-10 pM, 5 pM-9 pM, 5 pM-8 pM, 5 pM-7 pM, 5 pM-6 pM, 6 pM-10 pM, 6 pM-9 pM, 6 pM-8 pM, 6 pM-7 pM, 7 pM-10 pM, 7 pM-9 pM, 7 pM-8 pM, 8 pM-10 pM, 8 pM-9 pM, or 9 pM-10 pM. In some embodiments, a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1) is present in the medium at a concentration of 0.1 pM-0.5 pM (e.g., 0.1 pM, 0.15 pM, 0.2 pM, 0.25 pM, 0.3 pM, 0.35 pM, 0.4 pM, 0.45 pM, or 0.5 pM). In some embodiments, a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1) is present in the medium at a concentration of 0.25 pM. In some embodiments, an epidermal growth factor (e.g., betacellulin) is present in the medium at a concentration of 10 ng / ml-50 ng / ml. In some embodiments, an epidermal growth factor (e.g., betacellulin) is present in the medium at a concentration of 10 ng / ml-50 ng / ml, 10 ng / ml-40 ng / ml, 10 ng / ml-30 ng / ml, 10 ng / ml-20 ng / ml, 20 ng / ml-50 ng / ml, 20 ng / ml-40 ng / ml, 20 ng / ml-30 ng / ml, 30 ng / ml-50 ng / ml, 30 ng / ml-40 ng / ml, or 40 ng / ml-50 ng / ml. In some embodiments, an epidermal growth factor (e.g., betacellulin) is present in the medium at a concentration of 10 ng / ml-30 ng / ml (e.g., 10 ng / ml, 20 ng / ml, 20 ng / ml). In some embodiments, an epidermal growth factor (e.g., betacellulin) is present in the medium at a concentration of 20 ng / ml. In some embodiments, a notch signaling pathway inhibitor (e.g., y-secretase inhibitor such as XXI) is present in the medium at a concentration of 0.1 pM-10 pM. In some embodiments, a notch signaling pathway inhibitor (e.g., y-secretase inhibitor such as XXI) is present in the medium at a concentration of 0.1 pM-10 pM, 0.1 pM-9 pM, 0.1 pM-8 pM, 0.1 pM-7 pM, 0.1 pM-6 pM, 0.1 pM-5 pM, 0.1 pM-4 pM, 0.1 pM-3 pM, 0.1 pM-2 pM, 0.1 pM-1 pM, 0.1 pM-0.5 pM, 0.5 pM-10 pM, 0.5 pM-9 pM, 0.5 pM-8 pM, 0.5 pM-7 pM, 0.5 pM-6 pM, 0.5 pM-5 pM, 0.5 pM-4 pM, 0.5 pM-3 pM, 0.5 pM-2 pM, 0.5 pM-1 pM, 1 pM-10 pM, 1 pM-9 pM, 1 pM-8 pM, 1 pM-7 pM, 1 pM-6 pM, 1 pM-5 pM, 1 pM-4 pM, 1 pM-3 pM, 1 pM-2 pM, 2 pM-10 pM, 2 pM-9 pM, 2 pM-8 pM, 2 pM-7 pM, 2 pM-6 pM, 2 pM-5 pM, 2 pM-4 pM, 2 pM-3 pM, 3 pM-10 pM, 3 pM-9 pM, 3 pM-8 pM, 3 pM-7 pM, 3 pM-6 pM, 3 pM-5 pM, 3 pM-4 pM, 4 pM-10 pM, 4 pM-9 pM, 4 pM-8 pM, 4 pM-7 pM, 4 pM-6 pM, 4 pM-5 pM, 5 pM-10 pM, 5 pM-9 pM, 5 pM-8 pM, 5 pM-7 pM, 5 pM-6 pM, 6 pM-10 pM, 6 pM-9 pM, 6 pM-8 pM, 6 pM-7 pM, 7 pM-10 pM, 7 pM-9 pM, 7 pM-8 pM, 8 pM-10 pM, 8 pM-9 pM, or 9 pM-10 pM. In some embodiments, a notch signaling pathway inhibitor (e.g., y-secretase inhibitor such as XXI) is present in the medium at a concentration of 0.5 pM-5 pM (e.g., 0.5 pM, 1 pM, 1.5 pM, 2 pM, 2.5 pM, 3 pM, 3.5 pM, 4 pM, 4.5 pM, or 5 pM). In some embodiments, a notch signaling pathway inhibitor (e.g., y-secretase inhibitor such as XXI) is present in the medium at a concentration of 2 pM. In some embodiments, a TGFP-R1 kinase inhibitor (e.g., ALK5i) is present in the medium at a concentration of 1 pM-50 pM. In some embodiments, a TGFP-R1 kinase inhibitor (e.g., ALK5i) is present in the medium at a concentration of 1 pM-50 pM, 1 pM-40 pM, 1 pM-30 pM, 1 pM-20 pM, 1 pM-10 pM, 10 pM-50 pM, 10 pM-40 pM, 10 pM-30 pM, 10 pM-20 pM, 20 pM-50 pM, 20 pM-40 pM, 20 pM-30 pM, 30 pM-50 pM, 30 pM-40 pM, or 40 pM-50 pM. In some embodiments, a TGFP-R1 kinase inhibitor (e.g., ALK5i) is present in the medium at a concentration of 5 pM-20 pM (e.g., 5 pM, 10 pM, 15 pM, or 20 pM). In some embodiments, a TGFP-R1 kinase inhibitor (e.g., ALK5i) is present in the medium at a concentration of 10 pM. In some embodiments, a thyroid hormone (e.g., GC-1) is present in the medium at a concentration of 0.1 pM-10 pM. In some embodiments, a thyroid hormone (e.g., GC-1) is present in the medium at a concentration of 0.1 pM-10 pM, 0.1 pM-9 pM, 0.1 pM-8 pM, 0.1 pM-7 pM, 0.1 pM-6 pM, 0.1 pM-5 pM, 0.1 pM-4 pM, 0.1 pM-3 pM, 0.1 pM-2 pM, 0.1 pM-1 pM, 0.1 pM-0.5 pM, 0.5 pM-10 pM, 0.5 pM-9 pM, 0.5 pM-8 pM, 0.5 pM-7 pM, 0.5 pM-6 pM, 0.5 pM-5 pM, 0.5 pM-4 pM, 0.5 pM-3 pM, 0.5 pM-2 pM, 0.5 pM-1 pM, 1 pM-10 pM, 1 pM-9 pM, 1 pM-8 pM, 1 pM-7 pM, 1 pM-6 pM, 1 pM-5 pM, 1 pM-4 pM, 1 pM-3 pM, 1 pM-2 pM, 2 pM-10 pM, 2 pM-9 pM, 2 pM-8 pM, 2 pM-7 pM, 2 pM-6 pM, 2 pM-5 pM, 2 pM-4 pM, 2 pM-3 pM, 3 pM-10 pM, 3 pM-9 pM, 3 pM-8 pM, 3 pM-7 pM, 3 pM-6 pM, 3 pM-5 pM, 3 pM-4 pM, 4 pM-10 pM, 4 pM-9 pM, 4 pM-8 pM, 4 pM-7 pM, 4 pM-6 pM, 4 pM-5 pM, 5 pM-10 pM, 5 pM-9 pM, 5 pM-8 pM, 5 pM-7 pM, 5 pM-6 pM, 6 pM-10 pM, 6 pM-9 pM, 6 pM-8 pM, 6 pM-7 pM, 7 pM-10 pM, 7 pM-9 pM, 7 pM-8 pM, 8 pM-10 pM, 8 pM-9 pM, or 9 pM-10 pM. In some embodiments, a thyroid hormone (e.g., GC-1) is present in the medium at a concentration of 0.5 pM-5 pM (e.g., 0.5 pM, 1 pM, 1.5 pM, 2 pM, 2.5 pM, 3 pM, 3.5 pM, 4 pM, 4.5 pM, or 5 pM). In some embodiments, a thyroid hormone (e.g., GC-1) is present in the medium at a concentration of 1 pM. In some embodiments, a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN-193189) is present in the medium at a concentration of 0.05 pM-0.5 pM. In some embodiments, a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN-193189) is present in the medium at a concentration of 0.05 pM-0.5 pM, 0.1 pM-0.5 pM, 0.15 pM-0.5 pM, 0.2 pM-0.5 pM, 0.25 pM-0.5 pM, 0.3 pM-0.5 pM, 0.35 pM-0.5 pM, 0.4 pM-0.5 pM, 0.45 pM-0.5 pM, 0.05 pM-0.4 pM, 0.1 pM-0.4 pM, 0.15 pM-0.4 pM, 0.2 pM-0.4 pM, 0.25 pM-0.4 pM, 0.3 pM-0.4 pM, 0.35 pM-0.4 pM, 0.05 pM-0.3 pM, 0.1 pM-0.3 pM, 0.15 pM-0.3 pM, 0.2 pM-0.3 pM, 0.25 pM-0.3 pM, 0.05 pM-0.2 pM, 0.1 pM-0.2 pM, 0.15 pM-0.2 pM, or 0.05 pM-0.1 pM. In some embodiments, a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN-193189) is present in the medium at a concentration of 0.05 pM-0.2 pM (e.g., 0.05 pM, 0.1 pM, 0.15 pM, or 0.2 pM). In some embodiments, a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN-193189) is present in the medium at a concentration of 0.1 pM. In some embodiments, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., thiazovivin) is present in the medium at a concentration of 1 pM-10 pM. In some embodiments, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., thiazovivin) is present in the medium at a concentration of 1 pM-10 pM, 1 pM-9 pM, 1 pM-8 pM, 1 pM-7 pM, 1 pM-6 pM, 1 pM-5 pM, 1 pM-4 pM, 1 pM-3 pM, 1 pM-2 pM, 2 pM-10 pM, 2 pM-9 pM, 2 pM-8 pM, 2 pM-7 pM, 2 pM-6 pM, 2 pM-5 pM, 2 pM-4 pM, 2 pM-3 pM, 3 pM-10 pM, 3 pM-9 pM, 3 pM-8 pM, 3 pM-7 pM, 3 pM-6 pM, 3 pM-5 pM, 3 pM-4 pM, 4 pM-10 pM, 4 pM-9 pM, 4 pM-8 pM, 4 pM-7 pM, 4 pM-6 pM, 4 pM-5 pM, 5 pM-10 pM, 5 pM-9 pM, 5 pM-8 pM, 5 pM-7 pM, 5 pM-6 pM, 6 pM-10 pM, 6 pM-9 pM, 6 pM-8 pM, 6 pM-7 pM, 7 pM-10 pM, 7 pM-9 pM, 7 pM-8 pM, 8 pM-10 pM, 8 pM-9 pM, or 9 pM-10 pM. In some embodiments, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., thiazovivin) is present in the medium at a concentration of 1 pM- 5 pM (e.g., 1 pM, 1.5 pM, 2 pM, 2.5 pM, 3 pM, 3.5 pM, 4 pM, 4.5 pM, or 5 pM). In some embodiments, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., thiazovivin) is present in the medium at a concentration of 2.5 pM. In some embodiments, a protein kinase inhibitor (e.g., staurosporine) is present in the medium at a concentration of 0.5 nM- 10 nM. In some embodiments, a protein kinase inhibitor (e.g., staurosporine) is present in the medium at a concentration of 0.5 nM-10 nM, 0.5 nM-9 nM, 0.5 nM- 8 nM, 0.5 nM-7 nM, 0.5 nM-6 nM, 0.5 nM-5 nM, 0.5 nM-4 nM, 0.5 nM-3 nM, 0.5 nM-2 nM, 0.5 nM-1 nM, 1 nM-10 nM, 1 nM-9 nM, 1 nM- 8 nM, 1 nM-7 nM, 1 nM-6 nM, 1 nM-5 nM, 1 nM-4 nM, 1 nM-3 nM, 1 nM- 2 nM, 2 nM-10 nM, 2 nM-9 nM, 2 nM- 8 nM, 2 nM-7 nM, 2 nM-6 nM, 2 nM-5 nM, 2 nM-4 nM, 2 nM-3 nM, 3 nM-10 nM, 3 nM-9 nM, 3 nM- 8 nM, 3 nM-7 nM, 3 nM-6 nM, 3 nM-5 nM, 3 nM-4 nM, 4 nM-10 nM, 4 nM-9 nM, 4 nM- 8 nM, 4 nM-7 nM, 4 nM-6 nM, 4 nM-5 nM, 5 nM-10 nM, 5 nM-9 nM, 5 nM- 8 nM, 5 nM-7 nM, 5 nM-6 nM, 6 nM-10 nM, 6 nM-9 nM, 6 nM- 8 nM, 6 nM-7 nM, 7 nM-10 nM, 7 nM-9 nM, 7 nM- 8 nM, 8 nM-10 nM, 8 nM-9 nM, or 9 nM-10nM. In some embodiments, a protein kinase inhibitor (e.g., staurosporine) is present in the medium at a concentration of 1 nM-5 nM (e.g., 1 nM, 2 nM, 3 nM, 4 nM, or 5 nM). In some embodiments, a protein kinase inhibitor (e.g., staurosporine) is present in the medium at a concentration of 3 nM. In some embodiments, a histone methyltransferase EZH2 inhibitor (e.g., DZNEP) is present in the medium at a concentration of 0.05 pM-0.5 pM. In some embodiments, a histone methyltransferase EZH2 inhibitor (e.g., DZNEP) is present in the medium at a concentration of 0.05 pM-0.5 pM, 0.1 pM-0.5 pM, 0.15 pM-0.5 pM, 0.2 pM-0.5 pM, 0.25 pM-0.5 pM, 0.3 pM-0.5 pM, 0.35 pM-0.5 pM, 0.4 pM-0.5 pM, 0.45 pM-0.5 pM, 0.05 pM-0.4 pM, 0.1 pM-0.4 pM, 0.15 pM-0.4 pM, 0.2 pM-0.4 pM, 0.25 pM-0.4 pM, 0.3 pM-0.4 pM, 0.35 pM-0.4 pM, 0.05 pM-0.3 pM, 0.1 pM-0.3 pM, 0.15 pM-0.3 pM, 0.2 pM-0.3 pM, 0.25 pM-0.3 pM, 0.05 pM-0.2 pM, 0.1 pM-0.2 pM, 0.15 pM-0.2 pM, or 0.05 pM-0.1 pM. In some embodiments, a histone methyltransferase EZH2 inhibitor (e.g., DZNEP) is present in the medium at a concentration of 0.05 pM-0.2 pM (e.g., 0.05 pM, 0.1 pM, 0.15 pM, or 0.2 pM). In some embodiments, a histone methyltransferase EZH2 inhibitor (e.g., DZNEP) is present in the medium at a concentration of 0.1 pM. In some embodiments, retinoic acid is present in the medium at a concentration of 0.02 pM-0.5 pM. In some embodiments, retinoic acid is present in the medium at a concentration of 0.02 pM-0.5 pM, 0.05 pM-0.5 pM, 0.1 pM-0.5 pM, 0.15 pM-0.5 pM, 0.2 pM-0.5 pM, 0.25 pM-0.5 pM, 0.3 pM-0.5 pM, 0.35 pM-0.5 pM, 0.4 pM-0.5 pM, 0.45 pM-0.5 pM, 0.02 pM-0.4 pM, 0.05 pM-0.4 pM, 0.1 pM-0.4 pM, 0.15 pM-0.4 pM, 0.2 pM-0.4 pM, 0.25 pM-0.4 pM, 0.3 pM-0.4 pM, 0.35 pM-0.4 pM, 0.02 pM-0.3 pM, 0.05 pM-0.3 pM, 0.1 pM-0.3 pM, 0.15 pM-0.3 pM, 0.2 pM-0.3 pM, 0.25 pM-0.3 pM, 0.02 pM-0.2 pM, 0.05 pM-0.2 pM, 0.1 pM-0.2 pM, 0.15 pM-0.2 pM, 0.02 pM-0.1 pM, 0.05 pM-0.1 pM, or 0.02 pM-0.05 pM. In some embodiments, retinoic acid is present in the medium at a concentration of 0.02 pM-0.2 pM (e.g., 0.02 pM, 0.05 pM, 0.1 pM, 0.15 pM, or 0.2 pM). In some embodiments, retinoic acid is present in the medium at a concentration of 0.05 pM. In some embodiments, an acetyl CoA related metabolite (e.g., acetate) is present in the medium at a concentration of 0.1 mM-10 mM. In some embodiments, an acetyl CoA related metabolite (e.g., acetate) is present in the medium at a concentration of 0.1 mM-10 mM, 0.1 mM-9 mM, 0.1 mM-8 mM, 0.1 mM-7 mM, 0.1 mM-6 mM, 0.1 mM-5 mM, 0.1 mM-4 mM, 0.1 mM-3 mM, 0.1 mM-2 mM, 0.1 mM-1 mM, 0.1 mM-0.5 mM, 0.5 mM-10 mM, 0.5 mM-9 mM, 0.5 mM-8 mM, 0.5 mM-7 mM, 0.5 mM-6 mM, 0.5 mM-5 mM, 0.5 mM-4 mM, 0.5 mM-3 mM, 0.5 mM-2 mM, 0.5 mM-1 mM, 1 mM-10 mM, 1 mM-9 mM, 1 mM-8 mM, 1 mM-7 mM, 1 mM-6 mM, 1 mM-5 mM, 1 mM-4 mM, 1 mM-3 mM, 1 mM-2 mM, 2 mM-10 mM, 2 mM-9 mM, 2 mM-8 mM, 2 mM-7 mM, 2 mM-6 mM, 2 mM-5 mM, 2 mM-4 mM, 2 mM-3 mM, 3 mM-10 mM, 3 mM-9 mM, 3 mM-8 mM, 3 mM-7 mM, 3 mM-6 mM, 3 mM-5 mM, 3 mM-4 mM, 4 mM-10 mM, 4 mM-9 mM, 4 mM-8 mM, 4 mM-7 mM, 4 mM-6 mM, 4 mM-5 mM, 5 mM-10 mM, 5 mM-9 mM, 5 mM-8 mM, 5 mM-7 mM, 5 mM-6 mM, 6 mM-10 mM, 6 mM-9 mM, 6 mM-8 mM, 6 mM-7 mM, 7 mM-10 mM, 7 mM-9 mM, 7 mM-8 mM, 8 mM-10 mM, 8 mM-9 mM, or 9 mM-10 mM. In some embodiments, an acetyl CoA related metabolite (e.g., acetate) is present in the medium at a concentration of 0.5 mM-5 mM (e.g., 0.5 mM, 1 mM, 1.5 mM, 2 mM, 2.5 mM, 3 mM, 3.5 mM, 4 mM, 4.5 mM, or 5 mM). In some embodiments, an acetyl CoA related metabolite (e.g., acetate) is present in the medium at a concentration of 1 mM. In some embodiments, an HDAC inhibitor (e.g., P-hydroxybutyrate) is present in the medium at a concentration of 0.05 pM-0.5 pM. In some embodiments, an HDAC inhibitor (e.g., P-hydroxybutyrate) is present in the medium at a concentration of 0.05 pM-0.5 pM, 0.1 pM-0.5 pM, 0.15 pM-0.5 pM, 0.2 pM-0.5 pM, 0.25 pM-0.5 pM, 0.3 pM-0.5 pM, 0.35 pM-0.5 pM, 0.4 pM-0.5 pM, 0.45 pM-0.5 pM, 0.05 pM-0.4 pM, 0.1 pM-0.4 pM, 0.15 pM-0.4 pM, 0.2 pM-0.4 pM, 0.25 pM-0.4 pM, 0.3 pM-0.4 pM, 0.35 pM-0.4 pM, 0.05 pM-0.3 pM, 0.1 pM-0.3 pM, 0.15 pM-0.3 pM, 0.2 pM-0.3 pM, 0.25 pM-0.3 pM, 0.05 pM-0.2 pM, 0.1 pM-0.2 pM, 0.15 pM-0.2 pM, or 0.05 pM-0.1 pM. In some embodiments, an HDAC inhibitor (e.g., P-hydroxybutyrate) is present in the medium at a concentration of 0.1 pM-0.5 pM (e.g., 0.1 pM, 0.2 pM, 0.3 pM, 0.4 pM , 0.5 pM). In some embodiments, an HDAC inhibitor is present in the medium at a concentration of 0.2 pM. In some embodiments, a redox homeostasis regulator (e.g., taurine) is present in the medium at a concentration of 20 pM-100 pM. In some embodiments, a redox homeostasis regulator (e.g., taurine) is present in the medium at a concentration of 20 pM-100 pM, 20 pM-90 pM, 20 pM-80 pM, 20 pM-70 pM, 20 pM-60 pM, 20 pM-50 pM, 20 pM-40 pM, 20 pM-30 pM, 30 pM-100 pM, 30 pM-90 pM, 30 pM-80 pM, 30 pM-70 pM, 30 pM-60 pM, 30 pM-50 pM, 30 pM-40 pM, 40 pM-100 pM, 40 pM-90 pM, 40 pM-80 pM, 40 pM-70 pM, 40 pM-60 pM, 40 pM-50 pM, 50 pM-100 pM, 50 pM-90 pM, 50 pM-80 pM, 50 pM-70 pM, 50 pM-60 pM, 60 pM-100 pM, 60 pM-90 pM, 60 pM-80 pM, 60 pM-70 pM, 70 pM-100 pM, 70 pM-90 pM, 70 pM-80 pM, 80 pM-100 pM, 80 pM-90 pM, or 90 pM-100 pM. In some embodiments, a redox homeostasis regulator (e.g., taurine) is present in the medium at a concentration of 50 pM-100 pM (e.g., 50 pM, 60 pM, 70 pM, 80 pM, 90 pM, or 100 pM). In some embodiments, a redox homeostasis regulator (e.g., taurine) is present in the medium at a concentration of 90 pM. In some embodiments, a one carbon metabolism pathway intermediate (e.g., formate) is present in the medium at a concentration of 20 pM-100 pM. In some embodiments, a one carbon metabolism pathway intermediate (e.g., formate) is present in the medium at a concentration of 20 pM-100 pM, 20 pM-90 pM, 20 pM-80 pM, 20 pM-70 pM, 20 pM-60 pM, 20 pM-50 pM, 20 pM-40 pM, 20 pM-30 pM, 30 pM-100 pM, 30 pM-90 pM, 30 pM-80 pM, 30 pM-70 pM, 30 pM-60 pM, 30 pM-50 pM, 30 pM-40 pM, 40 pM-100 pM, 40 pM-90 pM, 40 pM-80 pM, 40 pM-70 pM, 40 pM-60 pM, 40 pM-50 pM, 50 pM-100 pM, 50 pM-90 pM, 50 pM-80 pM, 50 pM-70 pM, 50 pM-60 pM, 60 pM-100 pM, 60 pM-90 pM, 60 pM-80 pM, 60 pM-70 pM, 70 pM-100 pM, 70 pM-90 pM, 70 pM-80 pM, 80 pM-100 pM, 80 pM-90 pM, or 90 pM-100 pM. In some embodiments, a one carbon metabolism pathway intermediate (e.g., formate) is present in the medium at a concentration of 20 pM-80 pM (e.g., 20 pM, 30 pM, 40 pM, 50 pM, 60 pM, 70 pM, or 80 pM). In some embodiments, a one carbon metabolism pathway intermediate (e.g., formate) is present in the medium at a concentration of 50 pM. In some embodiments, a vitamin (e.g., biotin) is present in the medium at a concentration of 0.1 pM-5 pM. In some embodiments, a vitamin (e.g., biotin) is present in the medium at a concentration of 0.1 pM-5 pM, 0.1 pM-4 pM, 0.1 pM-3 pM, 0.1 pM-2 pM, 0.1 pM-1 pM, 0.1 pM-0.5 pM, 0.5 pM-5 pM, 0.5 pM-4 pM, 0.5 pM-3 pM, 0.5 pM-2 pM, 0.5 pM-1 pM, 1 pM-5 pM, 1 pM-4 pM, 1 pM-3 pM, 1 pM-2 pM, 2 pM-5 pM, 2 pM-4 pM, 2 pM-3 pM, 3 pM-5 pM, 3 pM-4 pM, or 4 pM-5 pM. In some embodiments, a vitamin (e.g., biotin) is present in the medium at a concentration of 0.5 pM-2 pM (e.g., 0.5 pM, 0.8 pM, 1 pM, 1.5 pM, 2 pM). In some embodiments, a vitamin (e.g., biotin) is present in the medium at a concentration of 0.8 pM. In some embodiments, glutamine (e.g., L-glutamine) is present in the medium at a concentration of 1 mM-10 mM. In some embodiments, glutamine (e.g., L-glutamine) is present in the medium at a concentration of 1 mM-10 mM, 1 mM-9 mM, 1 mM-8 mM, 1 mM-7 mM, 1 mM-6 mM, 1 mM-5 mM, 1 mM-4 mM, 1 mM-3 mM, 1 mM-2 mM, 2 mM-10 mM, 2 mM-9 mM, 2 mM-8 mM, 2 mM-7 mM, 2 mM-6 mM, 2 mM-5 mM, 2 mM-4 mM, 2 mM-3 mM, 3 mM-10 mM, 3 mM-9 mM, 3 mM-8 mM, 3 mM-7 mM, 3 mM-6 mM, 3 mM-5 mM, 3 mM-4 mM, 4 mM-10 mM, 4 mM-9 mM, 4 mM-8 mM, 4 mM-7 mM, 4 mM-6 mM, 4 mM-5 mM, 5 mM-10 mM, 5 mM-9 mM, 5 mM-8 mM, 5 mM-7 mM, 5 mM-6 mM, 6 mM-10 mM, 6 mM-9 mM, 6 mM-8 mM, 6 mM-7 mM, 7 mM-10 mM, 7 mM-9 mM, 7 mM-8 mM, 8 mM-10 mM, 8 mM-9 mM, or 9 mM-10 mM. In some embodiments, glutamine (e.g., L-glutamine) is present in the medium at a concentration of 2 mM-6 mM (e.g., 2 mM, 3 mM, 4 mM, 5 mM, or 6 mM). In some embodiments, glutamine (e.g., L-glutamine) is present in the medium at a concentration of 4 mM. In some embodiments, the medium comprises a PKC activator (e.g., PdBu) at a concentration of 0.2 pM-1 pM, a Wnt signaling pathway inhibitor (e.g., a tankyrase inhibitor such as NVP-TNKS656) at a concentration of 0.5 pM-5 pM, a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1) at a concentration of 0.1 pM-0.5 pM, an epidermal growth factor (e.g., betacellulin) at a concentration of 10 ng / ml-30 ng / ml, a notch signaling pathway inhibitor (e.g., y-secretase inhibitor such as XXI) at a concentration of 0.5 pM-5 pM, a TGFP-R1 kinase inhibitor (e.g., ALK5i) at a concentration of 5 pM-20 pM, a thyroid hormone (e.g., GC-1) at a concentration of 0.5 pM-5 pM, a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN-193189) at a concentration of 0.05 pM-0.2 pM, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., thiazovivin) at a concentration of 1 pM- 5 pM, a protein kinase inhibitor (e.g., staurosporine) at a concentration of 1 nM-5 nM, a histone methyltransferase EZH2 inhibitor (e.g., DZNEP) at a concentration of 0.05 pM-0.2 pM, retinoic acid at a concentration of 0.02 pM-0.2 pM, an acetyl CoA related metabolite (e.g., acetate) at a concentration of 0.5 mM-5 mM, an HD AC inhibitor (e.g., P-hydroxybutyrate) at a concentration of 0.1 pM-0.5 pM, a redox homeostasis regulator (e.g., taurine) at a concentration of 50 pM-100 pM, an one carbon metabolism pathway intermediate (e.g., formate) at a concentration of 20 pM-80 pM, a vitamin (e.g., biotin) at a concentration of 0.5 pM-2 pM, glutamine (e.g., L-glutamine) at a concentration of 2 mM-6 mM. In some embodiments, the medium comprises a PKC activator (e.g., PdBu) at a concentration of 0.5 pM, a Wnt signaling pathway inhibitor (e.g., a tankyrase inhibitor such as NVP-TNKS656) at a concentration of 2 pM, a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1) at a concentration of 0.25 pM, an epidermal growth factor (e.g., betacellulin) at a concentration of 20 ng / ml, a notch signaling pathway inhibitor (e.g., y-secretase inhibitor such as XXI) at a concentration of 2 pM, a TGFP-R1 kinase inhibitor (e.g., ALK5i) at a concentration of 10 pM, a thyroid hormone (e.g., GC-1) at a concentration of 1 pM, a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN-193189) at a concentration of 0.1 pM, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., thiazovivin) at a concentration of 2.5 pM, a protein kinase inhibitor (e.g., staurosporine) at a concentration of 3 nM, a histone methyltransferase EZH2 inhibitor (e.g., DZNEP) at a concentration of 0.1 pM, retinoic acid at a concentration of 0.05 pM, an acetyl CoA related metabolite (e.g., acetate) at a concentration of 4 mM, an HDAC inhibitor (e.g., P-hydroxybutyrate) at a concentration of 50 pM, a redox homeostasis regulator (e.g., taurine) at a concentration of 90 pM, an one carbon metabolism pathway intermediate (e.g., formate) at a concentration of 50 pM, a vitamin (e.g., biotin) at a concentration of 0.8 pM, glutamine (e.g., L-glutamine) at a concentration of 4 mM. In some embodiments, an in vitro composition described herein further comprises a water-soluble synthetic polymer. In some embodiments, the water-soluble synthetic polymer is polyvinyl alcohol (PVA), poloxamer, polyvinylpyrrolidone, polyethylene glycol (PEG), PEG copolymers, poly(N-isopropylacrylamide), or polyacrylamide, optionally wherein the water soluble synthetic polymer is polyvinyl alcohol. In some embodiments, the water water-soluble synthetic polymer is polyvinyl alcohol (PVA). In some embodiments, the water-soluble synthetic polymer has a concentration of 0.005% to 0.5% (w / v), 0.01% to 0.2% (w / v), 0.02% to 0.1% (w / v), or 0.03% to 0.08% (w / v) of the culture medium. In some embodiments, the watersoluble synthetic polymer has a concentration of 0.005% (w / v), 0.01% (w / v), 0.05% (w / v), 0.1% (w / v), 0.15% (w / v), 0.2% (w / v), 0.25% (w / v), 0.3% (w / v), 0.35% (w / v), to 0.4% (w / v), 0.45% (w / v), or 0.5% (w / v) of the medium. Polyvinyl alcohol described herein can refer to a watersoluble synthetic polymer that has an idealized formula [CH2CH(OH)]n, which can be either partially or completed hydrolyzed. In some cases, the polyvinyl alcohol is manufactured by either partial or complete hydrolysis of polyvinyl acetate to remove acetate groups. In some cases, the polyvinyl alcohol is at most 85% hydrolyzed, e.g., 80% hydrolyzed. The percentage of hydrolyzation measures the approximate percentage (e.g., average percentage) of acetate residue that is hydrolyzed in the polyvinyl acetate precursor polymer. In some cases, the polyvinyl alcohol is at least 85% hydrolyzed, e.g., 87-89% hydrolyzed, 87-90% hydrolyzed, or 99% hydrolyzed. In some embodiments, the polyvinyl alcohol is 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% hydrolyzed. In some embodiments, the water-soluble synthetic polymer is polyvinyl alcohol (PVA), and the PVA is at most 90% (e.g., 87%-89%) hydrolyzed. In some embodiments, the PVA is 80% hydrolyzed (e.g., in stages 1-4). In some embodiments, the PVA is 89% hydrolyzed (e.g., in stage 5). In some embodiments, an in vitro composition described herein comprises a population of pancreatic progenitor cells comprising cells that are PDXl-positive and NKX6.1-positive, and insulin-negative. In some embodiments, an in vitro composition comprising described herein comprises a population of pancreatic progenitor cells comprising cells that are PDXl-positive and NKX6.1-positive, and insulin-positive. In some embodiments, an in vitro composition comprising described herein comprises a population of pancreatic progenitor cells comprising cells that are PDXl-positive and NKX6.1-positive, and insulin-negative and cells that are PDXl-positive and NKX6.1-positive, and insulin-positive. In some embodiments, the population of pancreatic progenitor cells comprises more cells that are PDXl-positive, NKX6.1-positive, and insulin-negative than cells that are PDXl-positive, NKX6.1-positive and insulin-positive. In some embodiments, at least 50% (e.g., at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%) of the population of pancreatic progenitor cells are PDXl-positive, NKX6.1-positive, and insulin-negative. In some embodiments, no more than 50% (e.g., no more than 50%, no more than 40%, no more than 30%, no more than 20%, or no more than 10%) of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDX1 -positive, NKX6.1- positive, and insulin-positive. In some embodiments, 50%-90% (e.g., 50%-90%, 50%-80%, 50%-70%, 50%-60%, 60%-90%, 60%-80%, 60%-70%, 30%-80%, 70%-90%, 70%-80%, or 80%-90%) of the population of pancreatic progenitor cells are PDX1-positive, NKX6.1- positive, and insulin-negative. In some embodiments, 10%-50% (e.g., 10%-50%, 20%-50%, 30%-50%, 40%-50%, 10%-40%, 20%-40%, 30%-40%, 10%-30%, 20%-30%, or 10%-20%,) of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDX1-positive, NKX6.1- positive, and insulin-positive. In some embodiments, 50%-90% (e.g., 50%-90%, 50%-80%, 50%-70%, 50%-60%, 60%-90%, 60%-80%, 60%-70%, 30%-80%, 70%-90%, 70%-80%, or 80%-90%) of the population of pancreatic progenitor cells are PDX1-positive, NKX6.1- positive, and insulin-negative and 10%-50% (e.g., 10%-50%, 20%-50%, 30%-50%, 40%-50%, 10%-40%, 20%-40%, 30%-40%, 10%-30%, 20%-30%, or 10%-20%,) of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDX1-positive, NKX6.1- positive, and insulin-positive. In some embodiments, at least 50% of the population of pancreatic progenitor cells are PDX1-positive, NKX6.1- positive, and insulinnegative, and no more than 50% of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDX1-positive, NKX6.1- positive, and insulin-positive. In some embodiments, the population of pancreatic progenitor cells comprises more cells that are PDX1-positive, NKX6.1- positive, and insulin-positive than cells that are PDX1-positive, NKX6.1- positive, and insulin-negative. In some embodiments, at least 50% (e.g., at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%) of the population of pancreatic progenitor cells are PDX1-positive, NKX6.1- positive, and insulin-positive. In some embodiments, no more than 50% (e.g., no more than 50%, no more than 40%, no more than 30%, no more than 20%, or no more than 10%) of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDX1-positive, NKX6.1- positive, and insulin-negative. In some embodiments, 50%-90% (e.g., 50%-90%, 50%-80%, 50%-70%, 50%-60%, 60%-90%, 60%-80%, 60%-70%, 30%-80%, 70%-90%, 70%-80%, or 80%-90%) of the population of pancreatic progenitor cells are PDX1-positive, NKX6.1- positive, and insulin-positive. In some embodiments, 10%-50% (e.g., 10%-50%, 20%-50%, 30%-50%, 40%-50%, 10%-40%, 20%-40%, 30%-40%, 10%-30%, 20%-30%, or 10%-20%,) of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDX1-positive, NKX6.1- positive, and insulinnegative. In some embodiments, 50%-90% (e.g., 50%-90%, 50%-80%, 50%-70%, 50%-60%, 60%-90%, 60%-80%, 60%-70%, 30%-80%, 70%-90%, 70%-80%, or 80%-90%) of the population of pancreatic progenitor cells are PDX1-positive, NKX6.1- positive, and insulinpositive and 10%-50% (e.g., 10%-50%, 20%-50%, 30%-50%, 40%-50%, 10%-40%, 20%-40%, 30%-40%, 10%-30%, 20%-30%, or 10%-20%,) of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDX1-positive, NKX6.1- positive, and insulin-negative. In some embodiments, at least 50% of the population of pancreatic progenitor cells are PDX1-positive, NKX6.1- positive, and insulin-positive, and no more than 50% of the population of pancreatic progenitor cells are pancreatic progenitor cells that are PDX1-positive, NKX6.1-positive, and insulin-negative. Methods of producing pancreatic islet cells In aspects, the present disclosure relates to compositions and methods of generating endocrine cells from pancreatic progenitor cells or precursors. Certain exemplary detailed protocols of generating endocrine cells to provide at least one SC-P cell are described in U.S. Patent Application Publication No. US20150240212, US20150218522, US 20200332262, US 20210198632, US 20220090020, US 2021-0238553, US Patent 10,030,229; US Patent 10,443,042; and published application WO2022147056, each of which is herein incorporated by reference in its entirety. In some embodiments, a method of generating a population of endocrine cells leads to increased percentage of pancreatic a and / or 6 cells and decreased percentage of pancreatic EC cells when generating pancreatic P cells. In some embodiments, a method described herein may be used to obtain an enriched population of a cells. In some embodiments, a method described herein may be used to obtain an enriched population of P cells. In some embodiments, a method described herein may be used to obtain an enriched population of a cells and P cells. In some embodiments, a method described herein may be used to obtain an increased yield of pancreatic endocrine cells. The differentiation of hPSC cells to hormone-expressing pancreatic endocrine cells may be conducted by transitioning hPSC cells through major stages of embryonic development; differentiation to mesendoderm and definitive endoderm, establishment of the primitive gut endoderm, patterning of the posterior foregut, and specification and maturation of pancreatic endoderm and endocrine precursors. Through these stages, hPSC cells can obtain pancreatic endocrine phenotype and ability of glucose responsive insulin secretion in vitro. Generally, the at least one pancreatic SC-a, SC-P and / or SC-8 cell or precursor thereof, e.g., pancreatic progenitors produced according to the methods disclosed herein can comprise a mixture or combination of different cells, e.g., for example a mixture of cells such as a PDX1-positive pancreatic progenitors, pancreatic progenitors co-expressing PDX1 and NKX6-1, a Ngn3-positive endocrine progenitor cell, an insulin-positive endocrine cell (e.g., NKX6.1-positive, ISLl-positive cells, or P-like cells), and / or other pluripotent or stem cells. The at least one pancreatic a, P and / or 8 cell or precursor thereof can be produced according to any suitable culturing protocol to differentiate a stem cell or pluripotent cell to a desired stage of differentiation. In some embodiments, the at least one pancreatic a, P and / or 6 cell or the precursor thereof are produced by culturing at least one pluripotent cell for a period of time and under conditions suitable for the at least one pluripotent cell to differentiate into the at least one pancreatic a, P and / or 6 cell or the precursor thereof. In some embodiments, the at least one pancreatic a, P and / or 6 cell or precursor thereof is a substantially pure population of pancreatic a, P and / or 6 cells or precursors thereof. In some embodiments, a population of pancreatic a, P and / or 6 cells or precursors thereof comprises a mixture of pluripotent cells or differentiated cells. In some embodiments, a population pancreatic a, P and / or 6 cells or precursors thereof are substantially free or devoid of embryonic stem cells or pluripotent cells or iPS cells. In some embodiments, a method described herein produces a population of cells comprising pancreatic a, P and / or 6 cells at a ratio that resembles that of a natural pancreatic islet. In some embodiments, a method described herein comprises (i) culturing a first population of cells comprising pancreatic progenitor cells (e.g., cells that are PDX1-positive, NKX6.1-negative; or a mixture of cells that are PDX1-positive, NKX6.1-negative and cells that are PDX1-positive, NKX6.1-positive) in a first medium comprising a Forkhead Box 01 (FoxOl) inhibitor and a notch signaling pathway inhibitor for a period of time to obtain a second population of cells (e.g., a population of cells that comprises more PDX1-positive, NKX6.1-positive cells than the first population); and (ii) culturing the second population of cells in a second medium comprising a PKC activator and a Wnt signaling pathway inhibitor. In some embodiments, the method generates a population of cells comprising cells that are PDX1-positive, NKX6.1-positive, and insulin-positive. In some embodiments, a method described herein comprises culturing a first population of cells in a first medium, wherein the first population of cells comprises pancreatic progenitor cells that are PDXl-positive and NKX6.1 negative, and pancreatic progenitor cells that are PDXl-positive and NKX6.1 positive; and the first medium comprises a Forkhead Box 01 (FoxOl) inhibitor (e.g., AS 1842856 or a derivative thereof). In some embodiments, the first medium further comprises a notch signaling pathway inhibitor. In some embodiments, the notch signaling pathway inhibitor is a y-secretase inhibitor (e.g., XXI, DAPT or derivatives thereof). In some embodiments, the y-secretase inhibitor is XXI. In some embodiments, the first medium does not comprise a Wnt signaling pathway inhibitor. In some embodiments, the first population of cells comprises pancreatic progenitor cells that are PDXl-positive and NKX6.1 positive. In some embodiments, the first population of cells comprises more pancreatic progenitor cells that are PDXl-positive and NKX6.1 negative than pancreatic progenitor cells that are PDXl-positive and NKX6.1 positive. In some embodiments, the first population of cells comprises more pancreatic progenitor cells that are PDX1-positive and NKX6.1 positive than pancreatic progenitor cells that are PDXl-positive and NKX6.1 negative. In some embodiments, first medium further comprises a PKC activator (e.g., PdBU, TPB, phorbol 12-myristate 13-acetate, bryostatin 1, or derivatives thereof). In some embodiments, the PKC activator is PdBU. In some embodiments, the first medium further comprises one or more (e.g., 1, 2, 3, 4, 5) agents selected from a fibroblast growth factor (e.g., KGF), a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1), retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., triazovivin), and a TGF-P ligand (e.g., activin A). In some embodiments, the first medium further comprises a water-soluble synthetic polymer (e.g., PVA such as PVA80%). In some embodiments, the first medium comprises a FoxOl inhibitor (e.g., AS 1842856 or a derivative thereof), a notch signaling pathway inhibitor (e.g., y-secretase inhibitor such as XXI), a PKC activator (e.g., PdBU), a fibroblast growth factor (e.g., KGF), a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1), retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., triazovivin), and a TGF-P ligand (e.g., activin A), and a water-soluble synthetic polymer (e.g., PVA such as PVA80%). In some embodiments, the first population of cells are cultured in the first medium for a period of about 12-72 hours (e.g., about 12-72 hours, 12-66 hours, 12-60 hours, 12-54 hours, 1248 hours, 12-42 hours, 12-36 hours, 12-30 hours, 12-24 hours, 12-18 hours, 18-72 hours, 18-66 hours, 18-60 hours, 18-54 hours, 18-48 hours, 18-42 hours, 18-36 hours, 18-30 hours, 18-24 hours, 24-72 hours, 24-66 hours, 24-60 hours, 24-54 hours, 24-48 hours, 24-42 hours, 24-36 hours, 24-30 hours, 30-72 hours, 30-66 hours, 30-60 hours, 30-54 hours, 30-48 hours, 30-42 hours, 30-36 hours, 36-72 hours, 36-66 hours, 36-60 hours, 36-54 hours, 36-48 hours, 36-42 hours, 42-72 hours, 42-66 hours, 42-60 hours, 42-54 hours, 42-48 hours, 48-72 hours, 48-66 hours, 48-60 hours, 48-54 hours, 54-72 hours, 54-66 hours, 54-60 hours, 60-72 hours, 60-66 hours, or 66-72 hours). In some embodiments, the first population of cells are cultured in the first medium for a period of about 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, or 72 hours. In some embodiments, the first population of cells are cultured in the first medium for a period of about 24 hours. In some embodiments, the first population of cells are cultured in the first medium for a period of about 48 hours. In some embodiments, culturing the first population of cells in the first media for a contacting period described herein (e.g., 24 or 48 hours) results in a second population of cells. In some embodiments, the second population of cells comprises pancreatic progenitor cells that are PDXl-positive and NKX6.1 positive and pancreatic progenitor cells that are PDXl-positive and NKX6.1 negative. In some embodiments, the second population of cells comprises more pancreatic progenitor cells that are PDXl-positive and NKX6.1-positive than the first population of cells. In some embodiments, the second population of cells comprises more pancreatic progenitor cells that are PDXl-positive and NKX6.1 positive than pancreatic progenitor cells that are PDXl-positive and NKX6.1 negative. In some embodiments, the second population of cells comprises trace amounts (e.g., less than 5%, less than 4%, less than 3%, less than 2%, less than 1% of the second population of cells) of pancreatic progenitor cells that are PDXl-positive and NKX6.1 negative. In some embodiments, a method described herein further comprises culturing the second population of cells with a second medium comprising a Wnt signaling pathway inhibitor (e.g., a tankyrase inhibitor such as NVP-TNKS656). In some embodiments, the second medium comprises a PKC activator (e.g., PdBu). In some embodiments, the second medium further comprises one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10) agents selected from an epidermal growth factor (e.g., betacellulin), a thyroid hormone (e.g., GC-1), a TGFP-R1 kinase inhibitor (e.g., ALK5i), a notch signaling pathway inhibitor (e.g., a y-secretase inhibitor such as XXI), a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1), retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., triazovivin), a protein kinase inhibitor (e.g., staurosporine), a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN193189), and a histone methyltransferase EZH2 inhibitor (e.g., DZNep). In some embodiments, the second medium further comprises one or more (e.g., 1, 2, 3, 4) agents selected from an acetyl CoA related metabolite (e.g., acetate), an HDAC inhibitor (e.g., P-hydroxybutyrate), a redox homeostasis regulator (e.g., taurine), and a one carbon metabolism pathway intermediate (e.g., formate). In some embodiments, the second medium further comprises a vitamin (e.g., biotin). In some embodiments, the second medium further comprises glutamine. In some embodiments, the second medium further comprises a water soluble synthetic polymer (e.g., PVA such as PVA 87-89%). In some embodiments, the second medium does not comprise a FOXO1 inhibitor. In some embodiments, the second medium comprises a Wnt signaling pathway inhibitor (e.g., a tankyrase inhibitor such as NVP-TNKS656), a PKC activator (e.g., PdBu), an epidermal growth factor (e.g., betacellulin), a thyroid hormone (e.g., GC-1), a TGFP-R1 kinase inhibitor (e.g., ALK5i), a notch signaling pathway inhibitor (e.g., a y-secretase inhibitor such as XXI), a sonic hedgehog (SHH) signaling pathway inhibitor (e.g., SANT-1), retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., triazovivin), a protein kinase inhibitor (e.g., staurosporine), a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN193189), a histone methyltransferase EZH2 WO 2023 / 077140                                                 PCT / US2022 / 079017 inhibitor (e.g., DZNep), an acetyl CoA related metabolite (e.g., acetate), an HDAC inhibitor (e.g., P-hydroxybutyrate), a redox homeostasis regulator (e.g., taurine), a one carbon metabolism pathway intermediate (e.g., formate), a vitamin (e.g., biotin), glutamine and a water soluble synthetic polymer (e.g., PVA such as PVA 87-89%), and does not comprise a FOXO1 inhibitor. In some embodiments, the second population of cells are cultured in the second medium for a period of about 12-72 hours (e.g., about 12-72 hours, 12-66 hours, 12-60 hours, 12-54 hours, 12-48 hours, 12-42 hours, 12-36 hours, 12-30 hours, 12-24 hours, 12-18 hours, 18-72 hours, 18-66 hours, 18-60 hours, 18-54 hours, 18-48 hours, 18-42 hours, 18-36 hours, 18-30 hours, 18-24 hours, 24-72 hours, 24-66 hours, 24-60 hours, 24-54 hours, 24-48 hours, 24-42 hours, 24-36 hours, 24-30 hours, 30-72 hours, 30-66 hours, 30-60 hours, 30-54 hours, 30-48 hours, 30-42 hours, 30-36 hours, 36-72 hours, 36-66 hours, 36-60 hours, 36-54 hours, 36-48 hours, 36-42 hours, 42-72 hours, 42-66 hours, 42-60 hours, 42-54 hours, 42-48 hours, 48-72 hours, 48-66 hours, 48-60 hours, 48-54 hours, 54-72 hours, 54-66 hours, 54-60 hours, 60-72 hours, 60-66 hours, or 66-72 hours). In some embodiments, the second population of cells are cultured in the second medium for a period of about 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, or 72 hours. In some embodiments, the second population of cells are cultured in the second medium for a period of about 48 hours. In some embodiments, culturing the second population of cells in the second media for a contacting period described herein (e.g., 48 hours) results in a third population of cells. In some embodiments, the third population of cells comprises pancreatic progenitor cells that are PDX1-positive and NKX6.1-positive. In some embodiments, the third population of cells comprises cells that are ISL1-positive. In some embodiments, the third population of cells comprises cells that are ISLl-negative. In some embodiments, the third population of cells comprises cells that are ISL1-positive. In some embodiments, the third population of cells comprises more cells that are ISLl-positive than the first and second population of cells. In some embodiments, the third population of cells comprises more cells that are ISLl-negative than cells that are ISLl-positive. In some embodiments, the third population of cells comprises cells that are insulin-negative. In some embodiments, the third population of cells comprises cells that are insulin-positive. In some embodiments, the third population of cells comprises more cells that are insulin-negative than cells that are insulin-positive. In some embodiments, the third population of cells comprises more cells that are insulin-positive than the first and second population of cells. In some embodiments, the method further comprises culturing the third population of cells in a third medium comprising one or more agents selected from: a notch signaling pathway inhibitor (e.g., a y-secretase inhibitor such as XXI), a TGFP-R1 kinase inhibitor (e.g., ALK5i), a thyroid hormone (e.g., GC-1), a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN193189), a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., triazovivin), a protein kinase inhibitor (e.g., staurosporine), and a histone methyltransferase EZH2 inhibitor (e.g., DZNep). In some embodiments, the third medium further comprises one or more agents selected from an acetyl CoA related metabolite (e.g., acetate), an HDAC inhibitor (e.g., P-hydroxybutyrate), a redox homeostasis regulator (e.g., taurine), and an one carbon metabolism pathway intermediate (e.g., formate). In some embodiments, the third medium further comprises a vitamin (e.g., biotin). In some embodiments, the third medium further comprises glutamine. In some embodiments, the third medium further comprises a water soluble synthetic polymer (e.g., PVA such as PVA 87-89%). In some embodiments, the third medium does not comprise a Wnt signaling pathway inhibitor or a PKC activator. In some embodiments, the third medium comprises a notch signaling pathway inhibitor (e.g., a y-secretase inhibitor such as XXI), a TGFP-R1 kinase inhibitor (e.g., ALK5i), a thyroid hormone (e.g., GC-1), a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN193189), a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., triazovivin), a protein kinase inhibitor (e.g., staurosporine), and a histone methyltransferase EZH2 inhibitor (e.g., DZNep), an acetyl CoA related metabolite (e.g., acetate), an HDAC inhibitor (e.g., P-hydroxybutyrate), a redox homeostasis regulator (e.g., taurine), a one carbon metabolism pathway intermediate (e.g., formate), a vitamin (e.g., biotin), glutamine and a water soluble synthetic polymer (e.g., PVA such as PVA 87-89%), and does not comprise a Wnt signaling pathway inhibitor and a PKC activator. In some embodiments, the third population of cells are cultured in the third medium (e.g., the third medium that does not comprise a Wnt signaling pathway inhibitor or a PKC activator) for a period of about 24-96 hours (e.g., about 2496 hours, 24-84 hours, 24-72 hours, 24-60 hours, 24-48 hours, 24-36 hours, 36-96 hours, 36-84 hours, 36-72 hours, 36-60 hours, 36-48 hours, 48-96 hours, 48-84 hours, 48-72 hours, 48-60 hours, 60-96 hours, 60-84 hours, 60-72 hours, 72-96 hours, 72-84 hours, or 84-96 hours). In some embodiments, the third population of cells are cultured in the third medium for a period of about 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, or 96 hours. In some embodiments, the third population of cells are cultured in the third medium for a period of about 96 hours. In some embodiments, the third medium further comprises a Wnt signaling pathway inhibitor but does not comprise a PKC activator. In some embodiments, the third medium comprises Wnt signaling pathway inhibitor (e.g., a tankyrase inhibitor such as NVP-TNKS656), a notch signaling pathway inhibitor (e.g., a y-secretase inhibitor such as XXI), a TGFP-R1 kinase inhibitor (e.g., ALK5i), a thyroid hormone (e.g., GC-1), a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN193189), a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., triazovivin), a protein kinase inhibitor (e.g., staurosporine), and a histone methyltransferase EZH2 inhibitor (e.g., DZNep), an acetyl CoA related metabolite (e.g., acetate), an HDAC inhibitor (e.g., P-hydroxybutyrate), a redox homeostasis regulator (e.g., taurine), a one carbon metabolism pathway intermediate (e.g., formate), a vitamin (e.g., biotin), glutamine and a water soluble synthetic polymer (e.g., PVA such as PVA 87-89%), and does not comprise a PKC activator. In some embodiments, the third population of cells are cultured in the third medium (e.g., the third medium that comprises a Wnt signaling pathway inhibitor but not a PKC activator) for a period of about 24-48 hours (e.g., about 24-48 hours, 24-36 hours, or 36-48 hours), after which the Wnt signaling pathway inhibitor is removed from the third medium and the cells are further cultured for about 24-48 hours ((e.g., about 24-48 hours, 24-36 hours, or 3648 hours). In some embodiments, the third population of cells are cultured in the third medium (e.g., the third medium that comprises a Wnt signaling pathway inhibitor but not a PKC activator) for a period of about 48 hours, after which the Wnt signaling pathway inhibitor is removed from the third medium and the cells are further cultured for about 48 hours. In some embodiments, culturing the third population of cells in the third media for a contacting period described herein (e.g., 96 hours) results in a fourth population of cells. In some embodiments, the fourth population of cells comprises cells that are PDXl-positive and NKX6.1 positive. In some embodiments, the fourth population of cells comprises cells that are insulinpositive. In some embodiments, the fourth population of cells comprises cells that are PDXl-positive, NKX6.1 positive, and insulin-positive. In some embodiments, the fourth population of cells comprise cells that are IS LI-positive. In some embodiments, the fourth population of cells comprises cells that are ISL-1 negative. In some embodiments, at least 30% (e.g., at least 30%, at least 40%, at least 50%, or at least 60%)) of the fourth population of cells are insulin-positive. In some embodiments, 30%-50%, 30%-40%, or 40%-50% of the fourth population of cells are insulin-positive. In some embodiments, the method further comprises culturing the fourth population of cells in a fourth medium comprising one or more agents selected from: a TGFP-R1 kinase inhibitor (e.g., ALK5i), a thyroid hormone (e.g., GC-1), a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN193189), a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., triazovivin), a protein kinase inhibitor (e.g., staurosporine), and a histone methyltransferase EZH2 inhibitor (e.g., DZNep). In some embodiments, the fourth medium further comprises one or more agents selected from an acetyl CoA related metabolite (e.g., acetate), an HD AC inhibitor (e.g., P-hydroxybutyrate), a redox homeostasis regulator (e.g., taurine), and an one carbon metabolism pathway intermediate (e.g., formate). In some embodiments, the fourth medium further comprises a vitamin (e.g., biotin). In some embodiments, the fourth medium further comprises one or more of glutamine (e.g., L-glutamine), glutamate (e.g., L-glutamate), and carnitine (e.g., L-carnitine). In some embodiments, the fourth medium further comprises albumin (e.g., human serum albumin or HSA). In some embodiments, the fourth medium further comprises ZnSO4. In some embodiments, the fourth media does not comprise a Wnt signaling pathway inhibitor or a PKC activator. In some embodiments, the fourth medium comprises a TGFP-R1 kinase inhibitor (e.g., ALK5i), a thyroid hormone (e.g., GC-1), a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN193189), a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., triazovivin), a protein kinase inhibitor (e.g., staurosporine), and a histone methyltransferase EZH2 inhibitor (e.g., DZNep), an acetyl CoA related metabolite (e.g., acetate), an HDAC inhibitor (e.g., P-hydroxybutyrate), a redox homeostasis regulator (e.g., taurine), a one carbon metabolism pathway intermediate (e.g., formate), a vitamin (e.g., biotin), glutamine, glutamate, carnitine, albumin (e.g., human serum albumin or HSA), and ZnSO4, and does not comprise a Wnt signaling pathway inhibitor or a PKC activator. In some embodiments, the fourth population of cells are cultured in the fourth medium for a period of about 24-96 hours (e.g., about 24-96 hours, 24-84 hours, 24-72 hours, 24-60 hours, 24-48 hours, 24-36 hours, 36-96 hours, 36-84 hours, 36-72 hours, 36-60 hours, 36-48 hours, 48-96 hours, 48-84 hours, 48-72 hours, 48-60 hours, 60-96 hours, 60-84 hours, 60-72 hours, 72-96 hours, 72-84 hours, or 84-96 hours). In some embodiments, the fourth population of cells are cultured in the fourth medium for a period of about 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, or 96 hours. In some embodiments, the fourth population of cells are cultured in the fourth medium for a period of about 72 hours. In some embodiments, culturing the fourth population of cells in the fourth media for a contacting period described herein (e.g., 96 hours) results in a fifth population of cells. In some embodiments, a method described herein further comprises culturing the fifth population of cells in a fifth medium comprising glutamine, albumin (e.g., human serum albumin or HSA), and ZnSO4. In some embodiments, the fifth medium comprises glutamine, albumin (e.g., human serum albumin or HSA) and ZnSO4, and does not comprise any one of the agents selected from: a TGFP-R1 kinase inhibitor (e.g., ALK5i), a thyroid hormone (e.g., GC-1), a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN193189), a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., triazovivin), a protein kinase inhibitor (e.g., staurosporine), and a histone methyltransferase EZH2 inhibitor (e.g., DZNep). In some embodiments, the fifth media further comprises a histone methyltransferase EZH2 inhibitor (e.g., DZNep), an acetyl CoA related metabolite (e.g., acetate), an HDAC inhibitor (e.g., P-hydroxybutyrate), a redox homeostasis regulator (e.g., taurine), a one carbon metabolism pathway intermediate (e.g., formate), a vitamin (e.g., biotin), glutamine, glutamate, and carnitine. In some embodiments, the fifth medium comprises a histone methyltransferase EZH2 inhibitor (e.g., DZNep), an acetyl CoA related metabolite (e.g., acetate), an HDAC inhibitor (e.g., P-hydroxybutyrate), a redox homeostasis regulator (e.g., taurine), an one carbon metabolism pathway intermediate (e.g., formate), a vitamin (e.g., biotin), glutamate, glutamine, carnitine, albumin (e.g., human serum albumin or HSA), and ZnSO4, and does not comprise any one of the agents selected from: a TGFP-R1 kinase inhibitor (e.g., ALK5i), a thyroid hormone (e.g., GC-1), a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN193189), a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., thiazovivin), a protein kinase inhibitor (e.g., staurosporine), and a histone methyltransferase EZH2 inhibitor (e.g., DZNep). In some embodiments, the fifth medium comprises albumin (e.g., human serum albumin or HSA), and ZnSO4, and does not comprise any one of the agents selected from: a TGFP-R1 kinase inhibitor (e.g., ALK5i), a thyroid hormone (e.g., GC-1), a bone morphogenetic (BMP) signaling pathway inhibitor (e.g., LDN193189), a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor (e.g., triazovivin), a protein kinase inhibitor (e.g., staurosporine), a histone methyltransferase EZH2 inhibitor (e.g., DZNep), an acetyl CoA related metabolite (e.g., acetate), an HDAC inhibitor (e.g., P-hydroxybutyrate), a redox homeostasis regulator (e.g., taurine), an one carbon metabolism pathway intermediate (e.g., formate), a vitamin (e.g., biotin), carnitine, glutamate, and glutamine. In some embodiments, the fifth population of cells are cultured in the fifth medium for a period of about 96-240 hours (e.g., about 96-240 hours, 96-216 hours, 96-192 hours, 96-168 hours, 96-144 hours, 96-120 hours; 120-240 hours, 120-216 hours, 120-192 hours, 120-168 hours, 120-144 hours, 144-240 hours, 144-216 hours, 144-192 hours, 144-168 hours, 168-240 hours, 168-216 hours, 168-192 hours, 192-240 hours, 192-216 hours, or 192-240 hours). In some embodiments, the fifth population of cells are cultured in the fifth medium for a period of about 24, 48, 72, 96, 120, 144, 168, 192, 216, or 240 hours. In some embodiments, the fifth population of cells are cultured in the fifth medium for a period of about 192 hours. In some embodiments, culturing the fifth population of cells in the fifth media for a contacting period described herein (e.g., 192 hours) results in a sixth population of cells. In some embodiments, at least 15% (e.g., at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40% or more) of the sixth population of cells are NKX6.1-negative, ISL-positive; and wherein less than 12% (e.g., less than 12%, less than 10%, less than 8%, less than 6%, less than 4%, less than 2% or less) of the sixth population of cells are NKX6.1-negative, ISL-negative. In some embodiments, a method described herein comprises: (i) culturing a first population of cells in a first medium to obtain a second population of cells, wherein the first population of cells comprises pancreatic progenitor cells that are PDX1-positive and NKX6.1 negative, and pancreatic progenitor cells that are PDXl-positive and NKX6.1 positive; and the first medium comprises: a FoxOl inhibitor, a notch signaling pathway inhibitor, a PKC activator, a fibroblast growth factor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a TGF-P ligand, and a water-soluble synthetic polymer; (ii) culturing the second population of cells obtained in (i) with a second medium to obtain a third population of cells, wherein the second medium comprises: a Wnt signaling pathway inhibitor, a PKC activator, an epidermal growth factor, a thyroid hormone, a TGFP-R1 kinase inhibitor, a notch signaling pathway inhibitor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a bone morphogenetic (BMP) signaling pathway inhibitor, a histone methyltransferase EZH2 inhibitor, an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, a one carbon metabolism pathway intermediate, a vitamin, glutamine and a water soluble synthetic polymer (e.g., PVA), and wherein the second medium does not comprise a FOXO1 inhibitor; (iii) culturing the third population of cells obtained in (ii) with a third medium to obtain a fourth population of cells, wherein the third medium comprises: a notch signaling pathway inhibitor, a TGFP-R1 kinase inhibitor, a thyroid hormone, a bone morphogenetic (BMP) signaling pathway, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, and a histone methyltransferase EZH2 inhibitor, an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, an one carbon metabolism pathway intermediate, a vitamin, glutamine and a water soluble synthetic polymer, and wherein the third medium does not comprise a Wnt signaling pathway inhibitor and a PKC activator; (iv) culturing the fourth population of cells obtained in (iii) with a fourth medium to obtain a fifth population of cells, wherein the fourth medium comprises a notch signaling pathway inhibitor, a TGFP-R1 kinase inhibitor, a thyroid hormone, a bone morphogenetic (BMP) signaling pathway inhibitor, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a histone methyltransferase EZH2 inhibitor, an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, a one carbon metabolism pathway intermediate, a vitamin, glutamine, glutamate, carnitine, albumin, and ZnSO4, and wherein the fourth medium does not comprise a Wnt signaling pathway inhibitor and a PKC activator; and (v) culturing the fifth population of cells obtained in (iv) with a fifth medium to obtain a sixth population of cells, wherein the fifth medium comprises albumin (e.g., human serum albumin or HSA) and ZnSO4. In some embodiments, a method described herein further comprises generating the first population of cells comprising pancreatic progenitor cells that are PDX1-positive and NKX6.1 negative and pancreatic progenitor cells that are PDXl-positive and NKX6.1 positive. In some embodiments, the first population of cells are differentiated from stem cells (e.g., embryonic stem cells or pluripotent stem cells). In some embodiments, the stem cells (e.g., embryotic stem cells) are generated from the inner cell mass of blastocyst-stage embryos represent. Stem cells can be maintained in culture, renew for themselves, proliferate unlimitedly as undifferentiated ES cells, and are capable of differentiating into all cell types of the body as the ectoderm, mesoderm, and endoderm lineage cells or tissues. Cell types during pancreatic differentiation Aspects of the present disclosure provide cell types of the pancreatic lineage obtained during differentiation of stem cells to generate pancreatic islet cells. Such cells include any cell that is capable of differentiating into a pancreatic islet cell, including for example, a pluripotent stem cell, a definitive endoderm cell, a primitive gut tube cell, a pancreatic progenitor cell, or endocrine progenitor cell, when cultured under conditions suitable for differentiating the precursor cell into the pancreatic islet cell. Stem Cells “Stem cell” refers to a cell (e.g., plant stem cell, vertebrate stem cell) that has the ability both to self-renew and to generate a differentiated cell type (Morrison et al. (1997) Cell 88:287298). In the context of cell ontogeny, the adjective “differentiated,” or “differentiating” is a relative term. A “differentiated cell” is a cell that has progressed further down the developmental pathway than the cell it is being compared with. Thus, pluripotent stem cells can differentiate into lineage-restricted progenitor cells (e.g., mesodermal stem cells), which in turn can differentiate into cells that are further restricted (e.g., neuron progenitors), which can differentiate into end-stage cells (i.e., terminally differentiated cells, e.g., neurons, cardiomyocytes, etc.), which play a characteristic role in a certain tissue type, and can or cannot retain the capacity to proliferate further. Stem cells can be characterized by both the presence of specific markers (e.g., proteins, RNAs, etc.) and the absence of specific markers. Stem cells can also be identified by functional assays both in vitro and in vivo, particularly assays relating to the ability of stem cells to give rise to multiple differentiated progeny. In an embodiment, the host cell is an adult stem cell, a somatic stem cell, a non- embryonic stem cell, an embryonic stem cell, hematopoietic stem cell, an include pluripotent stem cells, and a trophoblast stem cell. Stem cells of interest include pluripotent stem cells (PSCs). The term “pluripotent stem cell” or “PSC” is used herein to mean a stem cell capable of producing all cell types of the organism. Therefore, a PSC can give rise to cells of all germ layers of the organism (e.g., the endoderm, mesoderm, and ectoderm of a vertebrate). Pluripotent cells are capable of forming teratomas and of contributing to ectoderm, mesoderm, or endoderm tissues in a living organism. Pluripotent stem cells of plants are capable of giving rise to all cell types of the plant (e.g., cells of the root, stem, leaves, etc.). PSCs of animals can be derived in a number of different ways. For example, embryonic stem cells (ESCs) are derived from the inner cell mass of an embryo (Thomson et. al, Science. 1998 Nov. 6; 282(5391): 1145-7) whereas induced pluripotent stem cells (iPSCs) are derived from somatic cells (Takahashi et. al, Cell. 2007 Nov. 30; 13 l(5):861-72; Takahashi et. al, Nat Protoc. 2007; 2(12):3081-9; Yu et. al, Science. 2007 Dec. 21; 318(5858): 1917-20. Epub 2007 Nov. 20). Because the term PSC refers to pluripotent stem cells regardless of their derivation, the term PSC encompasses the terms ESC and iPSC, as well as the term embryonic germ stem cells (EGSC), which are another example of a PSC. PSCs can be in the form of an established cell line, they can be obtained directly from primary embryonic tissue, or they can be derived from a somatic cell. By “embryonic stem cell” (ESC) is meant a PSC that is isolated from an embryo, typically from the inner cell mass of the blastocyst. ESC lines are listed in the NIH Human Embryonic Stem Cell Registry, e.g. hESBGN-Ol, hESBGN-02, hESBGN-03, hESBGN-04 (BresaGen, Inc ); HES-1, HES-2, HES-3, HES-4, HES-5, HES-6 (ES Cell International); Miz-hESl (MizMedi Hospital-Seoul National University); HSF-1, HSF-6 (University of California at San Francisco); and Hl, H7, H9, H13, H14 (Wisconsin Alumni Research Foundation (WiCell Research Institute)). Stem cells of interest also include embryonic stem cells from other primates, such as Rhesus stem cells and marmoset stem cells. The stem cells can be obtained from any mammalian species, e.g., human, equine, bovine, porcine, canine, feline, rodent, e.g. mice, rats, hamster, primate, etc. (Thomson et al. (1998) Science 282: 1145; Thomson et al. (1995) Proc. Natl. Acad. Sci USA 92:7844; Thomson et al. (1996) Biol. Reprod. 55:254; Shamblott et al., Proc. Natl. Acad. Sci. USA 95: 13726, 1998). In culture, ESCs typically grow as flat colonies with large nucleo-cytoplasmic ratios, defined borders and prominent nucleoli. In addition, ESCs express SSEA-3, SSEA-4, TRA-1-60, TRA-1-81, and Alkaline Phosphatase, but not SSEA-1. Examples of methods of generating and characterizing ESCs may be found in, for example, U.S. Pat. No. 7,029,913, U.S. Pat. No. 5,843,780, and U.S. Pat. No. 6,200,806, each of which is incorporated herein by its entirety. Methods for proliferating hESCs in the undifferentiated form are described in WO 99 / 20741, WO 01 / 51616, and WO 03 / 020920, each of which is incorporated herein by its entirety. By “embryonic germ stem cell” (EGSC) or “embryonic germ cell” or “EG cell,” it is meant a PSC that is derived from germ cells and / or germ cell progenitors, e.g., primordial germ cells, i.e. those that can become sperm and eggs. Embryonic germ cells (EG cells) are thought to have properties similar to embryonic stem cells as described above. Examples of methods of generating and characterizing EG cells may be found in, for example, U.S. Pat. No. 7, 153,684; Matsui, Y., et al., (1992) Cell 70:841; Shamblott, M., et al. (2001) Proc. Natl. Acad. Sci. USA 98: 113; Shamblott, M., et al. (1998) Proc. Natl. Acad. Sci. USA, 95: 13726; and Koshimizu, U., et al. (1996) Development, 122: 1235, each of which are incorporated herein by its entirety. By “induced pluripotent stem cell” or “iPSC,” it is meant a PSC that is derived from a cell that is not a PSC (i.e., from a cell this is differentiated relative to a PSC). iPSCs can be derived from multiple different cell types, including terminally differentiated cells. iPSCs have an ES cell-like morphology, growing as flat colonies with large nucleo-cytoplasmic ratios, defined borders and prominent nuclei. In addition, iPSCs express one or more key pluripotency markers known by one of ordinary skill in the art, including but not limited to Alkaline Phosphatase, SSEA3, SSEA4, Sox2, Oct3 / 4, Nanog, TRA160, TRA181, TDGF 1, Dnmt3b, FoxD3, GDF3, Cyp26al, TERT, and zfp42. Examples of methods of generating and characterizing iPSCs can be found in, for example, Patent Publication Nos. US20090047263, US20090068742, US20090191159, US20090227032, US20090246875, and US20090304646, each of which are incorporated herein by its entirety. Generally, to generate iPSCs, somatic cells are provided with reprogramming factors (e.g., Oct4, SOX2, KLF4, MYC, Nanog, Lin28, etc.) known in the art to reprogram the somatic cells to become pluripotent stem cells. By “somatic cell,” it is meant any cell in an organism that, in the absence of experimental manipulation, does not ordinarily give rise to all types of cells in an organism. In other words, somatic cells are cells that have differentiated sufficiently that they do not naturally generate cells of all three germ layers of the body, i.e., ectoderm, mesoderm and endoderm. For example, somatic cells can include both neurons and neural progenitors, the latter of which is able to naturally give rise to all or some cell types of the central nervous system but cannot give rise to cells of the mesoderm or endoderm lineages. In certain examples, the stem cells can be undifferentiated (e.g., a cell not committed to a specific lineage) prior to exposure to at least one cell maturation factor according to the methods as disclosed herein, whereas in other examples it may be desirable to differentiate the stem cells to one or more intermediate cell types prior to exposure of the at least one cell maturation factor (s) described herein. For example, the stems cells may display morphological, biological or physical characteristics of undifferentiated cells that can be used to distinguish them from differentiated cells of embryo or adult origin. In some examples, undifferentiated cells may appear in the two dimensions of a microscopic view in colonies of cells with high nuclear / cytoplasmic ratios and prominent nucleoli. The stem cells may be themselves (for example, without substantially any undifferentiated cells being present) or may be used in the presence of differentiated cells. In certain examples, the stem cells may be cultured in the presence of suitable nutrients and optionally other cells such that the stem cells can grow and optionally differentiate. For example, embryonic fibroblasts or fibroblast-like cells may be present in the culture to assist in the growth of the stem cells. The fibroblast may be present during one stage of stem cell growth but not necessarily at all stages. For example, the fibroblast may be added to stem cell cultures in a first culturing stage and not added to the stem cell cultures in one or more subsequent culturing stages. Stem cells used in all aspects of the present invention can be any cells derived from any kind of tissue (for example embryonic tissue such as fetal or pre-fetal tissue, or adult tissue), which stem cells have the characteristic of being capable under appropriate conditions of producing progeny of different cell types, e.g., derivatives of all of at least one of the 3 germinal layers (endoderm, mesoderm, and ectoderm). These cell types may be provided in the form of an established cell line, or they may be obtained directly from primary embryonic tissue and used immediately for differentiation. Included are cells listed in the NIH Human Embryonic Stem Cell Registry, e.g. hESBGN-Ol, hESBGN-02, hESBGN-03, hESBGN-04 (BresaGen, Inc.); HES-1, HES-2, HES-3, HES-4, HES-5, HES-6 (ES Cell International); Miz-hESl (MizMedi Hospital-Seoul National University); HSF-1, FISF-6 (University of California at San Francisco); and Hl, H7, H9, H13, H14 (Wisconsin Alumni Research Foundation (WiCell Research Institute)). In some embodiments, the source of human stem cells or pluripotent stem cells used for chemically-induced differentiation into mature, insulin positive cells did not involve destroying a human embryo. In another embodiment, the stem cells can be isolated from tissue including solid tissue. In some embodiments, the tissue is skin, fat tissue (e.g., adipose tissue), muscle tissue, heart or cardiac tissue. In other embodiments, the tissue is for example but not limited to, umbilical cord blood, placenta, bone marrow, or chondral. Stem cells of interest also include embryonic cells of various types, exemplified by human embryonic stem (hES) cells, described by Thomson et al, (1998) Science 282: 1145; embryonic stem cells from other primates, such as Rhesus stem cells (Thomson et al. (1995) Proc. Natl. Acad. Sci. USA 92:7844); marmoset stem cells (Thomson et al. (1996) Biol. Reprod. 55:254); and human embryonic germ (hEG) cells (Shambloft et al., Proc. Natl. Acad. Sci. USA 95: 13726, 1998). Also of interest are lineage committed stem cells, such as mesodermal stem cells and other early cardiogenic cells (see Reyes et al, (2001) Blood 98:2615-2625; Eisenberg & Bader (1996) Circ Res. 78(2):205-16; etc.) The stem cells may be obtained from any mammalian species, e.g., human, equine, bovine, porcine, canine, feline, rodent, e.g., mice, rats, hamster, primate, etc. In some embodiments, a human embryo was not destroyed for the source of pluripotent cell used on the methods and compositions as disclosed herein. A mixture of cells from a suitable source of endothelial, muscle, and / or neural stem cells can be harvested from a mammalian donor by methods known in the art. A suitable source is the hematopoietic microenvironment. For example, circulating peripheral blood, preferably mobilized (i.e., recruited), may be removed from a subject. In an embodiment, the stem cells can be reprogrammed stem cells, such as stem cells derived from somatic or differentiated cells. In such an embodiment, the de-differentiated stem cells can be for example, but not limited to, neoplastic cells, tumor cells and cancer cells or alternatively induced reprogrammed cells such as induced pluripotent stem cells or iPS cells. Definitive Endoderm Cells The definitive endoderm can be generated in vivo from the inner cell mass by the process of gastrulation of embryogenesis, in which epiblast cells are instructed to form the three germ layers. Definitive endoderm can give rise to diverse cells and tissues that contribute to vital organs as the pancreatic P cells, liver hepatocytes, lung alveolar cells, thyroid, thymus, and the epithelial lining of the alimentary and respiratory tract. It is different from the primitive endoderm of extraembryonic tissues, which can give rise to the visceral and parietal endoderm. The definitive endoderm derived from ES cells is theoretically capable of becoming any endoderm derivatives. Precise patterning of anterior-posterior axis of the definitive endoderm can eventually form the primitive gut tube. The definitive endoderm-derived primitive gut tube induces the pharynx, esophagus, stomach, duodenum, small and large intestine along the anterior-posterior axis as well as associated organs, including pancreas, lung, thyroid, thymus, parathyroid, and liver. The anterior portion of the foregut of the primitive gut tube becomes lung, thyroid, esophagus, and stomach. The pancreas, liver, and duodenum originate from the posterior portion of the foregut. The midgut and hindgut of primitive gut tube gives rise to the small and large intestine. The anterior foregut expresses developmental markers, NK2 homeobox 1 (NKX2-1) and SRY (sex determining region Y)-box 2 (SOX2); the posterior foregut expresses hematopoietically expressed homeobox (HHEX), pancreatic and duodenal homeobox 1 (PDX1), one cut homeobox 1 (ONECUT1, known as HNF6), and hepatocyte nuclear factor 4 alpha (HNF4A); and the midgut / hindgut expresses caudal type homeobox 1 (CDX1), caudal type homeobox 2 (CDX2), and motor neuron and pancreas homeobox 1 (MNX1) (3, 19, 20). As described herein definitive endoderm cells of use herein can be derived from any source or generated in accordance with any suitable protocol. In some aspects, pluripotent stem cells, e.g., iPSCs or hESCs, are differentiated to endoderm cells. In some aspects, the endoderm cells (stage 1) are further differentiated, e.g., to primitive gut tube cells (stage 2), PDX1-positive pancreatic progenitor cells (stage 3), NKX6.1-positive pancreatic progenitor cells (stage 4), or Ngn3-positive endocrine progenitor cells or insulin-positive endocrine cells (stage 5), followed by induction or maturation to SC-P cells (stage 6). In some embodiments, definitive endoderm cells can be obtained by differentiating at least some pluripotent cells in a population into definitive endoderm cells, e.g., by contacting a population of pluripotent cells with i) at least one growth factor from the TGF-P superfamily, and ii) a WNT signaling pathway activator, to induce the differentiation of at least some of the pluripotent cells into definitive endoderm cells, wherein the definitive endoderm cells express at least one marker characteristic of definitive endoderm. Any growth factor from the TGF-P superfamily capable of inducing the pluripotent stem cells to differentiate into definitive endoderm cells (e.g., alone, or in combination with a WNT signaling pathway activator) can be used in the method provided herein. In some embodiments, the growth factor from the TGF-P superfamily comprises Activin A. In some embodiments, the growth factor from the TGF-P superfamily comprises growth differentiating factor 8 (GDF8). Any WNT signaling pathway activator capable of inducing the pluripotent stem cells to differentiate into definitive endoderm cells (e.g., alone, or in combination with a growth factor from the TGF-P superfamily) can be used in the method provided herein. In some embodiments, the WNT signaling pathway activator comprises CHIR99021. In some embodiments, the WNT signaling pathway activator comprises Wnt3a recombinant protein. In some embodiments, differentiating at least some pluripotent cells in a population into definitive endoderm cells is achieved by a process of contacting a population of pluripotent cells with i) Activin A, and ii) CHIR99021 for a suitable period of time, e.g., about 2 days, about 3 days, about 4 days, or about 5 days to induce the differentiation of at least some of the pluripotent cells in the population into definitive endoderm cells, wherein the definitive endoderm cells express at least one marker characteristic of definitive endoderm. In some embodiments, the process comprises contacting a population of pluripotent cells with activin A and CHIR99021 for 1 day, and then with activin A (in the absence of CHIR99021) for a further 1 or 2 days. In some examples, the method comprises differentiating pluripotent cells into definitive endoderm cells by contacting a population of pluripotent cells with a suitable concentration of the growth factor from the TGF-0 superfamily (e.g., Activin A), such as, about 10 ng / mL, about 20 ng / mL, about 50 ng / mL, about 75 ng / mL, about 80 ng / mL, about 90 ng / mL, about 95 ng / mL, about 100 ng / mL, about 110 ng / mL, about 120 ng / mL, about 130 ng / mL, about 140 ng / mL, about 150 ng / mL, about 175 ng / mL, about 180 ng / mL, about 200 ng / mL, about 250 ng / mL, or about 300 ng / mL. In some embodiments, the method comprises use of about 70-130 ng.ml, 80120 ng / ml, or 90-110 ng / ml Activin A for differentiation of pluripotent cells into definitive endoderm cells. In some embodiments, the method comprises use of about 100 ng / mL Activin A for differentiation of pluripotent cells into definitive endoderm cells. In some embodiments, the method comprises use of about 200 ng / mL Activin A for differentiation of pluripotent cells into definitive endoderm cells. In some examples, the method comprises differentiating pluripotent cells into definitive endoderm cells by contacting a population of pluripotent cells with a suitable concentration of the WNT signaling pathway activator (e.g., CHIR99021), such as, about 0.01 pM, about 0.05 pM, about 0.1 pM, about 0.2 pM, about 0.5 pM, about 0.8 pM, about 1 pM, about 1.5 pM, about 2 pM, about 2.5 pM, about 3 pM, about 3.5 pM, about 4 pM, about 5 pM, about 8 pM, about 10 pM, about 12 pM, about 15 pM, about 20 pM, about 30 pM, about 50 pM, about 100 pM, or about 200 pM. In some embodiments, the method comprises use of about 1-5 pM or 2-4 pM CHIR99021 for differentiation of pluripotent cells into definitive endoderm cells. In some embodiments, the method comprises use of about 2 pM CHIR99021 for differentiation of pluripotent cells into definitive endoderm cells. In some embodiments, the method comprises use of about 3 pM CHIR99021 for differentiation of pluripotent cells into definitive endoderm cells. In some embodiments, the method comprises use of about 5 pM CHIR99021 for differentiation of pluripotent cells into definitive endoderm cells. In some embodiments, the cells are further contacted with a water-soluble synthetic polymer. In some embodiments, the water-soluble synthetic polymer is polyvinyl alcohol. In some cases, the polyvinyl alcohol is at least 78% hydrolyzed, e.g., 79-81% hydrolyzed, 87-89% hydrolyzed, 87-90% hydrolyzed, or 99% hydrolyzed. In some embodiments, the polyvinyl alcohol is 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% hydrolyzed. In some embodiments, the PVA is 80% hydrolyzed. In some embodiments, a definitive endoderm cell produced by the methods as disclosed herein expresses at least one marker selected from the group consisting of: Nodal, Tmprss2, Tmem30b, Stl4, Spink3, Sh3gl2, Ripk4, RablS, Npnt, Clic6, Cldn5, Cacnalb, Bnipl, Anxa4, Emb, FoxAl, Soxl7, and Rbm35a, wherein the expression of at least one marker is upregulated to by a statistically significant amount in the definitive endoderm cell relative to the pluripotent stem cell from which it was derived. In some embodiments, a definitive endoderm cell produced by the methods as disclosed herein does not express by a statistically significant amount at least one marker selected the group consisting of: Gata4, SPARC, AFP and Dab2 relative to the pluripotent stem cell from which it was derived. In some embodiments, a definitive endoderm cell produced by the methods as disclosed herein does not express by a statistically significant amount at least one marker selected the group consisting of: Zicl, Pax6, Flkl and CD31 relative to the pluripotent stem cell from which it was derived. In some embodiments, a definitive endoderm cell produced by the methods as disclosed herein has a higher level of phosphorylation of Smad2 by a statistically significant amount relative to the pluripotent stem cell from which it was derived. In some embodiments, a definitive endoderm cell produced by the methods as disclosed herein has the capacity to form gut tube in vivo. In some embodiments, a definitive endoderm cell produced by the methods as disclosed herein can differentiate into a cell with morphology characteristic of a gut cell, and wherein a cell with morphology characteristic of a gut cell expresses FoxA2 and / or Claudin6. In some embodiments, a definitive endoderm cell produced by the methods as disclosed herein can be further differentiated into a cell of endoderm origin. In some embodiments, a population of pluripotent stem cells are cultured in the presence of at least one P cell differentiation factor prior to any differentiation or during the first stage of differentiation. One can use any pluripotent stem cell, such as a human pluripotent stem cell, or a human iPS cell or any of pluripotent stem cell as discussed herein or other suitable pluripotent stem cells. In some embodiments, a P cell differentiation factor as described herein can be present in the culture medium of a population of pluripotent stem cells or may be added in bolus or periodically during growth (e.g. replication or propagation) of the population of pluripotent stem cells. In certain examples, a population of pluripotent stem cells can be exposed to at least one P cell differentiation factor prior to any differentiation. In other examples, a population of pluripotent stem cells may be exposed to at least one P cell differentiation factor during the first stage of differentiation. Primitive Gut Tube Cells Aspects of the disclosure involve primitive gut tube cells. Primitive gut tube cells of use herein can be derived from any source or generated in accordance with any suitable protocol. In some aspects, definitive endoderm cells are differentiated to primitive gut tube cells. In some aspects, the primitive gut tube cells are further differentiated, e.g., to PDXl-positive pancreatic progenitor cells, NKX6.1-positive pancreatic progenitor cells, Ngn3-positive endocrine progenitor cells, insulin-positive endocrine cells, followed by induction or maturation to SC-P cells. In some embodiments, primitive gut tube cells can be obtained by differentiating at least some definitive endoderm cells in a population into primitive gut tube cells, e.g., by contacting definitive endoderm cells with at least one growth factor from the fibroblast growth factor (FGF) family, to induce the differentiation of at least some of the definitive endoderm cells into primitive gut tube cells, wherein the primitive gut tube cells express at least one marker characteristic of primitive gut tube cells. Any growth factor from the FGF family capable of inducing definitive endoderm cells to differentiate into primitive gut tube cells (e.g., alone, or in combination with other factors) can be used in the method provided herein. In some embodiments, the at least one growth factor from the FGF family comprises keratinocyte growth factor (KGF). In some embodiments, the at least one growth factor from the FGF family comprises FGF2. In some embodiments, the at least one growth factor from the FGF family comprises FGF8B. In some embodiments, the at least one growth factor from the FGF family comprises FGF10. In some embodiments, the at least one growth factor from the FGF family comprises FGF21. In some embodiments, primitive gut tube cells can be obtained by differentiating at least some definitive endoderm cells in a population into primitive gut tube cells, e.g., by contacting definitive endoderm cells with KGF for a certain period of time, e.g., about 1 day, about 2 days, about 3 days, or about 4 days, to induce the differentiation of at least some of the definitive endoderm cells into primitive gut tube cells. In some embodiments, the method comprises differentiating definitive endoderm cells into primitive gut tube cells by contacting definitive endoderm cells with a suitable concentration of the growth factor from the FGF family (e.g., KGF), such as, about 10 ng / mL, about 20 ng / mL, about 50 ng / mL, about 75 ng / mL, about 80 ng / mL, about 90 ng / mL, about 95 ng / mL, about 100 ng / mL, about 110 ng / mL, about 120 ng / mL, about 130 ng / mL, about 140 ng / mL, about 150 ng / mL, about 175 ng / mL, about 180 ng / mL, about 200 ng / mL, about 250 ng / mL, or about 300 ng / mL. In some embodiments, the method comprises use of about 20-80 ng / ml, 30-70 ng / ml, or 40-60 ng / mL KGF for differentiation of definitive endoderm cells into primitive gut tube cells. WO 2023 / 077140                                                 PCT / US2022 / 079017 In some embodiments, the method comprises use of about 50 ng / mL KGF for differentiation of definitive endoderm cells into primitive gut tube cells. In some embodiments, the method comprises use of about 100 ng / mL KGF for differentiation of definitive endoderm cells into primitive gut tube cells. 5          In some embodiments, the cells are further contacted with a water-soluble synthetic polymer. In some embodiments, the water-soluble synthetic polymer is polyvinyl alcohol. In some cases, the polyvinyl alcohol is at least 78% hydrolyzed, e.g., 79-81% hydrolyzed, 87-89% hydrolyzed, 87-90% hydrolyzed, or 99% hydrolyzed. In some embodiments, the polyvinyl alcohol (PVA) is 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 10   91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% hydrolyzed. In some embodiments, the PVA is 80% hydrolyzed. PDX1 -positive Pancreatic Progenitor Cells Aspects of the disclosure involve PDX1-positive pancreatic progenitor cells. PDX1-15 positive pancreatic progenitor cells of use herein can be derived from any source or generated in accordance with any suitable protocol. In some aspects, primitive gut tube cells are differentiated to PDX1 -positive pancreatic progenitor cells. In some aspects, the PDXl-positive pancreatic progenitor cells are NKX6.1 negative, and can be further differentiated to, e.g., NKX6.1-positive pancreatic progenitor cells, Ngn3-positive endocrine progenitor cells, insulin-positive endocrine 20 cells, followed by induction or maturation to SC-P cells. In some aspects, PDXl-positive pancreatic progenitor cells can be obtained by differentiating at least some primitive gut tube cells in a population into PDXl-positive pancreatic progenitor cells, e.g., by contacting primitive gut tube cells with one or more of i) at least one BMP signaling pathway inhibitor, ii) a growth factor from TGF-P superfamily, iii) at 25 least one growth factor from the FGF family, iv) at least one SHH pathway inhibitor, v) at least one retinoic acid (RA) signaling pathway activator; vi) at least one protein kinase C activator, and vii) a ROCK inhibitor to induce the differentiation of at least some of the primitive gut tube cells into PDXl-positive pancreatic progenitor cells, wherein the PDXl-positive pancreatic progenitor cells express PDX1. 30            In some aspects, PDXl-positive pancreatic progenitor cells can be obtained by differentiating at least some primitive gut tube cells in a population into PDXl-positive pancreatic progenitor cells, e.g., by contacting primitive gut tube cells with one or more of i) at least one BMP signaling pathway inhibitor, ii) a growth factor from TGF-P superfamily, iii) at least one growth factor from the FGF family, iv) at least one SHH pathway inhibitor, v) at least 35 one retinoic acid (RA) signaling pathway activator; and vi) at least one protein kinase C activator, to induce the differentiation of at least some of the primitive gut tube cells into PDX1- WO 2023 / 077140                                                 PCT / US2022 / 079017 positive pancreatic progenitor cells, wherein the PDXl-positive pancreatic progenitor cells express PDX1. In some embodiments, PDXl-positive pancreatic progenitor cells can be obtained by differentiating at least some primitive gut tube cells in a population into PDXl-positive pancreatic progenitor cells, e.g., by contacting primitive gut tube cells with one or more of i) at least one BMP signaling pathway inhibitor, ii) at least one growth factor from the FGF family, iii) at least one SHH pathway inhibitor, iv) at least one retinoic acid (RA) signaling pathway activator; and v) at least one protein kinase C activator, to induce the differentiation of at least some of the primitive gut tube cells into PDXl-positive pancreatic progenitor cells, wherein the PDXl-positive pancreatic progenitor cells express PDX1. In some embodiments, PDXl-positive pancreatic progenitor cells can be obtained by differentiating at least some primitive gut tube cells in a population into PDXl-positive pancreatic progenitor cells, e.g., by contacting primitive gut tube cells with i) at least one SHH pathway inhibitor, ii) at least one retinoic acid (RA) signaling pathway activator; and iii) at least one protein kinase C activator, wherein the PDX1 -positive pancreatic progenitor cells express PDX1. In some embodiments, PDXl-positive pancreatic progenitor cells can be obtained by differentiating at least some primitive gut tube cells in a population into PDXl-positive pancreatic progenitor cells, e.g., by contacting primitive gut tube cells with i) at least one growth factor from the FGF family, and ii) at least one retinoic acid (RA) signaling pathway activator, to induce the differentiation of at least some of the primitive gut tube cells into PDXl-positive pancreatic progenitor cells, wherein the PDX1 -positive pancreatic progenitor cells express PDX1. Any BMP signaling pathway inhibitor capable of inducing primitive gut tube cells to differentiate into PDXl-positive pancreatic progenitor cells (e.g., alone, or with any combination of a growth factor from TGF-P superfamily, at least one growth factor from the FGF family, at least one SHH pathway inhibitor, at least one retinoic acid signaling pathway activator, at least one protein kinase C activator, and ROCK inhibitor) can be used in the method provided herein. In some embodiments, the BMP signaling pathway inhibitor comprises LDN193189 or DMH-1. In some examples, the method comprises contacting primitive gut tube cells with a concentration of BMP signaling pathway inhibitor (e.g., LDN1931189), such as, about 30 nM, about 40 nM, about 50 nM, about 60 nM, about 70 nM, about 80 nM, about 90 nM, about 100 nM, about 110 nM, about 120 nM, about 130 nM, about 140 nM, about 150 nM, about 160 nM, about 170 nM, about 180 nM, about 190 nM, about 200 nM, about 210 nM, about 220 nM, about 230 nM, about 240 nM, about 250 nM, about 280 nM, about 300 nM, about 400 nM, about 500 nM, or about IpM. In some examples, the method comprises contacting primitive gut tube cells with a concentration of BMP signaling pathway inhibitor (e.g., DMH-1), such as, about 0.01 pM, about 0.02pM, about 0.05pM, about O.lpM, about 0.2pM, about 0.5 pM, about 0.8 pM, about 1 pM, about 1.2 pM, about 1.5pM, about 1.75pM, about 2 pM, about 2.2 pM, about 2.5pM, about 2.75pM, about 3 pM, about 3.25 pM, about 3.5 pM, about 3.75 pM, about 4 pM, about 4.5 pM, about 5 pM, about 8 pM, about 10 pM, about 15 pM, about 20 pM, about 30 pM, about 40 pM, about 50 pM, or about 100 pM. In some examples, the method comprises contacting primitive gut tube cells with a concentration of BMP signaling pathway inhibitor (e.g., DMH-1), such as, about 220-280 nM, about 230-270 nM, about 240-260 nM, or about 245-255 nM. In some examples, the method comprises contacting primitive gut tube cells with a concentration of BMP signaling pathway inhibitor (e.g., DMH-1) about 250 nM. Any growth factor from the TGF-P superfamily capable of inducing primitive gut tube cells to differentiate into PDXl-positive pancreatic progenitor cells (e.g., alone, or with any combination of at least one BMP signaling pathway inhibitor, a growth factor from the FGF family, at least one SHH pathway inhibitor, at least one retinoic acid signaling pathway activator, at least one protein kinase C activator, and ROCK inhibitor) can be used. In some embodiments, the growth factor from TGF-P family comprises Activin A. In some embodiments, the growth factor from TGF-P family comprises GDF8. In some examples, the method comprises contacting primitive gut tube cells with a concentration of a growth factor from TGF-P superfamily (e.g., Activin A), such as, about 5 ng / mL, about 7.5 ng / mL, about 8 ng / mL, about 9 ng / mL, about 10 ng / mL, about 11 ng / mL, about 12 ng / mL, about 13 ng / mL, about 14 ng / mL, about 15 ng / mL, about 16 ng / mL, about 17 ng / mL, about 18 ng / mL, about 19 ng / mL, about 20 ng / mL, about 21 ng / mL, about 22 ng / mL, about 23 ng / mL, about 24 ng / mL, about 25 ng / mL, about 26 ng / mL, about 27 ng / mL, about 28 ng / mL, about 29 ng / mL, about 30 ng / mL, about 35 ng / mL, about 40 ng / mL, about 50 ng / mL, or about 100 ng / mL. In some examples, the method comprises contacting primitive gut tube cells with a concentration of a growth factor from TGF-P superfamily (e.g., Activin A), such as, about 17-23 ng / ml, about 18-22 ng / ml, or about 19-21 ng / ml. In some examples, the method comprises contacting primitive gut tube cells with a concentration of a growth factor from TGF-P superfamily (e.g., Activin A) of about 20 ng / ml. Any growth factor from the FGF family capable of inducing primitive gut tube cells to differentiate into PDXl-positive pancreatic progenitor cells (e.g., alone, or with any combination of at least one BMP signaling pathway inhibitor, a growth factor from TGF-P superfamily, at least one SHH pathway inhibitor, at least one retinoic acid signaling pathway activator, at least one protein kinase C activator, and ROCK inhibitor) can be used. In some embodiments, the at least one growth factor from the FGF family comprises keratinocyte growth factor (KGF). In some embodiments, the at least one growth factor from the FGF family is selected from the group consisting of FGF2, FGF8B, FGF10, and FGF21. In some examples, the method comprises contacting primitive gut tube cells with a concentration of a growth factor from FGF family (e.g., KGF), such as, about 10 ng / mL, about 20 ng / mL, about 50 ng / mL, about 75 ng / mL, about 80 ng / mL, about 90 ng / mL, about 95 ng / mL, about 100 ng / mL, about 110 ng / mL, about 120 ng / mL, about 130 ng / mL, about 140 ng / mL, about 150 ng / mL, about 175 ng / mL, about 180 ng / mL, about 200 ng / mL, about 250 ng / mL, or about 300 ng / mL. In some examples, the method comprises contacting primitive gut tube cells with a concentration of a growth factor from FGF family (e.g., KGF), such as, about 20-80 ng / ml, about 30-70 ng / ml, about 40-60 ng / ml, or about 45-55 ng / ml. In some examples, the method comprises contacting primitive gut tube cells with a concentration of a growth factor from FGF family (e.g., KGF) of about 50 ng / ml. Any SHH pathway inhibitor capable of inducing primitive gut tube cells to differentiate into PDXl-positive pancreatic progenitor cells (e.g., alone, or with any combination of at least one BMP signaling pathway inhibitor, at least one growth factor from the FGF family, a growth factor from TGF-P superfamily, at least one retinoic acid signaling pathway activator, at least one protein kinase C activator, and ROCK inhibitor) can be used. In some embodiments, the SHH pathway inhibitor comprises Santi. In some examples, the method comprises contacting primitive gut tube cells with a concentration of a SHH pathway inhibitor (e.g., Santi), such as, about 0.001 pM, about 0.002 pM, about 0.005 pM, about 0.01 pM, about 0.02 pM, about 0.03pM, about 0.05pM, about 0.08 pM, about O.lpM, about 0.12 pM, about 0.13 pM, about 0.14 pM, about 0.15 pM, about 0.16 pM, about 0.17 pM, about 0.18 pM, about 0.19 pM, about 0.2 pM, about 0.21pM, about 0.22pM, about 0.23pM, about 0.24 pM, about 0.25 pM, about 0.26 pM, about 0.27 pM, about 0.28 pM, about 0.29 pM, about 0.3 pM, about 0.31 pM, about 0.32 pM, about 0.33 pM, about 0.34 pM, about 0.35 pM, about 0.4 pM, about 0.45 pM, about 0.5 pM, about 0.6 pM, about 0.8 pM, about 1 pM, about 2 pM, or about 5 pM. In some examples, the method comprises contacting primitive gut tube cells with a concentration of a SHH pathway inhibitor (e.g., Santi), such as, about 220-280 nM, about 230-270 nM, about 240260 nM, or about 245-255 nM. In some examples, the method comprises contacting primitive gut tube cells with a concentration of a SHH pathway inhibitor (e.g., Santi) of about 250 nM. Any RA signaling pathway activator capable of inducing primitive gut tube cells to differentiate into PDXl-positive pancreatic progenitor cells (e.g., alone, or with any combination of at least one BMP signaling pathway inhibitor, at least one growth factor from the FGF family, at least one SHH pathway inhibitor, at least one protein kinase C activator, and ROCK inhibitor) can be used. In some embodiments, the RA signaling pathway activator comprises retinoic acid. In some examples, the method comprises contacting primitive gut tube cells with a concentration of an RA signaling pathway activator (e.g., retinoic acid), such as, about 0.02 pM, about O.lpM, about 0.2 pM, about 0.25 pM, about 0.3 pM, about 0.4 pM, about 0.45 pM, about 0.5 pM, about 0.55 pM, about 0.6 pM, about 0.65 pM, about 0.7 pM, about 0.75 pM, about 0.8 pM, about 0.85 pM, about 0.9 pM, about 1 pM, about 1.1 pM, about 1.2 pM, about 1.3 pM, about 1.4 pM, about 1.5 pM, about 1.6 pM, about 1.7 pM, about 1.8 pM, about 1.9 pM, about 2 pM, about 2.1 pM, about 2.2 pM, about 2.3 pM, about 2.4 pM, about 2.5 pM, about 2.6 pM, about 2.7 pM, about 2.8 pM, about 3 pM, about 3.2 pM, about 3.4 pM, about 3.6 pM, about 3.8 pM, about 4 pM, about 4.2 pM, about 4.4 pM, about 4.6 pM, about 4.8 pM, about 5 pM, about 5.5 pM, about 6 pM, about 6.5 pM, about 7 pM, about 7.5 pM, about 8 pM, about 8.5 pM, about 9 pM, about 9.5 pM, about 10 pM, about 12 pM, about 14 pM, about 15 pM, about 16 pM, about 18 pM, about 20 pM, about 50 pM, or about 100 pM. In some examples, the method comprises contacting primitive gut tube cells with a concentration of an RA signaling pathway activator (e.g., retinoic acid), such as, about 1.7-2.3 pM, about 1.8-2.2 pM, or about 1.9-2.1 pM. In some examples, the method comprises contacting primitive gut tube cells with a concentration of an RA signaling pathway activator (e.g., retinoic acid) of about 2 pM. Any PKC activator capable of inducing primitive gut tube cells to differentiate into PDX1-positive pancreatic progenitor cells (e.g., alone, or with any combination of at least one BMP signaling pathway inhibitor, at least one growth factor from the FGF family, at least one SHH pathway inhibitor, at least one RA signaling pathway activator, and ROCK inhibitor) can be used. In some embodiments, the PKC activator comprises PdBU. In some embodiments, the PKC activator comprises TPPB. In some examples, the method comprises contacting primitive gut tube cells with a concentration of a PKC activator (e.g., PdBU or TPPB), such as, about 10 nM, 50 nM, 100 nM, 150 nM, 200 nM, 250 nM, 300 nM, 350 nM, 400 nM, 450 nM, 500 nM, 550 nM, 600 nM, 650 nM, 700 nM, 750 nM, 800 nM, 850 nM, 900 nM, 950 nM, 1 pM, 10 pM, about 20 pM, about 50 pM, about 75 pM, about 80 pM, about 100 pM, about 120 pM, about 140 pM, about 150 pM, about 175 pM, about 180 pM, about 200 pM, about 210 pM, about 220 pM, about 240 pM, about 250 pM, about 260 pM, about 280 pM, about 300 pM, about 320 pM, about 340 pM, about 360 pM, about 380 pM, about 400 pM, about 420 pM, about 440 pM, about 460 pM, about 480 pM, about 500 pM, about 520 pM, about 540 pM, about 560 pM, about 580 pM, about 600 pM, about 620 pM, about 640 pM, about 660 pM, about 680 pM, about 700 pM, about 750 pM, about 800 pM, about 850 pM, about 900 pM, about 1 mM, about 2 mM, about 3 mM, about 4 mM, or about 5 mM. In some embodiments, the method comprises contacting primitive gut tube cells with a concentration of a PKC activator (e.g., PdBU or TPPB) of 10 nM-1 mM, 10 nM-500 pM, 10 nM-1 pM, 10-800 nM, 100-900 nM, 300-800 nM, 300-600 nM, 400-600 nM, 450-550 nM, or about 500 nM. In some examples, the method comprises contacting primitive gut tube cells with a concentration of a PKC activator (e.g., PdBU or TPPB), such as, about 450-550 mM, about 475-525 nM, about 490-510 nM, or about 495-505 nM. In some examples, the method comprises contacting primitive gut tube cells with a concentration of a PKC activator (e.g., PdBU or TPPB) of about 500 nM. In some embodiments, primitive gut tube cells are not treated with a PKC activator (e.g., PDBU). Any ROCK inhibitor capable of inducing primitive gut tube cells to differentiate into PDX1-positive pancreatic progenitor cells (e.g., alone, or with any combination of at least one BMP signaling pathway inhibitor, at least one growth factor from the FGF family, at least one SHH pathway inhibitor, PKC activator, and at least one RA signaling pathway activator) can be used. In some embodiments, the ROCK inhibitor comprises Thiazovivin, Y-27632, Fasudil / HA1077, or H-l 152. In some embodiments, the ROCK inhibitor comprises Y-27632. In some embodiments, the ROCK inhibitor comprises Thiazovivin. In some examples, the method comprises contacting primitive gut tube cells with a concentration of a ROCK inhibitor (e.g., Y-27632 or Thiazovivin), such as, about 0.2 pM, about 0.5 pM, about 0.75 pM, about 1 pM, about 2 pM, about 3 pM, about 4 pM, about 5 pM, about 6 pM, about 7 pM, about 7.5 pM, about 8 pM, about 9 pM, about 10 pM, about 11 pM, about 12 pM, about 13 pM, about 14 pM, about 15 pM, about 16 pM, about 17 pM, about 18 pM, about 19 pM, about 20 pM, about 21 pM, about 22 pM, about 23 pM, about 24 pM, about 25 pM, about 26 pM, about 27 pM, about 28 pM, about 29 pM, about 30 pM, about 35 pM, about 40 pM, about 50 pM, or about 100 pM. In some examples, the method comprises contacting primitive gut tube cells with a concentration of a ROCK inhibitor (e.g., Y-27632 or Thiazovivin), such as, about 2.2-2.8 pM, about 2.3-2.7 pM, or about 2.4-2.6 pM. In some examples, the method comprises contacting primitive gut tube cells with a concentration of a ROCK inhibitor (e.g., Y-27632 or Thiazovivin) of about 2.5 pM. In some embodiments, the cells are further contacted with a water-soluble synthetic polymer. In some embodiments, the water-soluble synthetic polymer is polyvinyl alcohol. In some cases, the polyvinyl alcohol is at least 78% hydrolyzed, e.g., 79-81% hydrolyzed, 87-89% hydrolyzed, 87-90% hydrolyzed, or 99% hydrolyzed. In some embodiments, the polyvinyl alcohol (PVA) is 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% hydrolyzed. In some embodiments, the PVA is 80% hydrolyzed. In some embodiments, PDXl-positive pancreatic progenitor cells can be obtained by differentiating at least some primitive gut tube cells in a population into PDXl-positive pancreatic progenitor cells, e.g., by contacting primitive gut tube cells with retinoic acid, KGF, Santi, DMH-1, PdBU, thiazovivin, and Activin A, for a suitable period of time, e.g., about 1 day, about 2 days, about 3 days, or about 4 days. In some embodiments, PDXl-positive pancreatic progenitor cells can be obtained by differentiating at least some primitive gut tube cells in a population into PDX1-positive pancreatic progenitor cells, e.g., by contacting primitive gut tube cells with retinoic acid, KGF, Santi, DMH-1, PdBU, thiazovivin, and Activin A, for about 2 days. In some embodiments, PDXl-positive pancreatic progenitor cells can be obtained by differentiating at least some primitive gut tube cells in a population into PDXl-positive pancreatic progenitor cells, e.g., by contacting primitive gut tube cells with retinoic acid, KGF, Santi, DMH-1, PdBU, thiazovivin, and Activin A for 1 day, followed by contacting the cells with retinoic acid, KGF, Santi, PdBU, thiazovivin, and Activin A for 1 day (in the absence of DMH-1). NKX6.1 -positive Pancreatic Progenitor Cells Aspects of the disclosure involve NKX6.1-positive pancreatic progenitor cells. NKX6.1-positive pancreatic progenitor cells of use herein can be derived from any source or generated in accordance with any suitable protocol. In some aspects, PDXl-positive, NKX6.1-negative pancreatic progenitor cells are differentiated to PDXl-positive, NKX6.1-positive pancreatic progenitor cells. In some aspects, the NKX6.1-positive pancreatic progenitor cells are further differentiated, e.g., to Ngn3-positive endocrine progenitor cells, or insulin-positive endocrine cells, followed by induction or maturation to SC-P cells. In some aspects, a method of producing a NKX6.1-positive pancreatic progenitor cell from a PDXl-positive pancreatic progenitor cell comprises contacting a population of cells (e.g., under conditions that promote cell clustering and / or promoting cell survival) comprising PDXl-positive pancreatic progenitor cells with at least two P cell-differentiation factors comprising a) at least one growth factor from the fibroblast growth factor (FGF) family, b) a sonic hedgehog pathway inhibitor, and optionally c) a low concentration of a retinoic acid (RA) signaling pathway activator, to induce the differentiation of at least one PDXl-positive pancreatic progenitor cell in the population into NKX6.1-positive pancreatic progenitor cells, wherein the NKX6.1-positive pancreatic progenitor cells expresses NKX6.1. In some embodiments, the PDXl-positive, NKX6.1-positive pancreatic progenitor cells are obtained by contacting PDXl-positive pancreatic progenitor cells with i) at least one growth factor from the FGF family, ii) at least one SHH pathway inhibitor, and optionally iii) a RA signaling pathway activator, to induce the differentiation of at least some of the PDXl-positive pancreatic progenitor cells into PDXl-positive, NKX6.1-positive pancreatic progenitor cells, wherein the PDXl-positive, NKX6.1- positive pancreatic progenitor cells express PDX1 and NKX6.1. In some embodiments, the PDXl-positive, NKX6.1-positive pancreatic progenitor cells are obtained by contacting PDXl-positive pancreatic progenitor cells with i) at least one growth 74 factor from the FGF family, ii) at least one SHH pathway inhibitor, and optionally iii) a RA signaling pathway activator, iv) ROCK inhibitor, and v) at least one growth factor from the TGF-P superfamily, to induce the differentiation of at least some of the PDX1-positive pancreatic progenitor cells into PDX1-positive, NKX6.1-positive pancreatic progenitor cells. In some embodiments, following 3, 4, or 5 days of contacting the PDX1-positive, NKX6.1-positive pancreatic progenitor cells are obtained by contacting PDX1-positive pancreatic progenitor cells with i) at least one growth factor from the FGF family, ii) at least one SHH pathway inhibitor, and optionally iii) a RA signaling pathway activator, iv) ROCK inhibitor, and v) at least one growth factor from the TGF-P superfamily; the cells are then contacted with i) at least one growth factor from the FGF family, ii) at least one SHH pathway inhibitor, and optionally iii) a RA signaling pathway activator, iv) ROCK inhibitor, and v) at least one growth factor from the TGF-P superfamily, and vi) a PKC activator and optionally vii) a gamma-secretase inhibitor. In some embodiments, the PDX1-positive, NKX6.1-positive pancreatic progenitor cells are obtained by contacting PDX1-positive pancreatic progenitor cells under conditions that promote cell clustering with at least one growth factor from the FGF family. In some embodiments, the growth factor from the FGF family is KGF. In some embodiments, the disclosure provides for a method in which a first population of cells comprising PDX1-positive, NKX6.1-negative cells is cultured in a media comprising any one or combination of: i) at least one growth factor from the FGF family, ii) at least one SHH pathway inhibitor, iii) a RA signaling pathway activator, iv) a ROCK inhibitor, and v) a growth factor from the TGF-P superfamily for a period of about 1, 2, 3, 4 or 5 days (e.g., 2-4, 3-4, or 4-5 days); thereby generating a second population of cells. In some embodiments, the second population of cells is then incubated in a composition comprising any one or combination of: i) at least one growth factor from the FGF family, ii) at least one SHH pathway inhibitor, iii) a RA signaling pathway activator, iv) a ROCK inhibitor, v) a growth factor from the TGF-P superfamily, vi) a PKC activator, vii) a FoxOl inhibitor, and optionally viii) a notch signaling inhibitor for about 1, 2, or 3 days (e.g., 1-2, 1-3, or 2-3 days). In some embodiments, in the media for culturing the first population of cells, the growth factor from the FGF family is present at a concentration of about 45-55 ng / ml, about 4654 ng / ml, about 47-53 ng / ml, about 48-52 ng / ml, or about 49-51 ng / ml, the SHH pathway inhibitor is present at a concentration of about 200-300 nM, about 220-280 nM, or about 240-260 nM, the RA signaling pathway activator is present at a concentration of about 1.7-2.3 pM, about 1.8-2.2 pM, or about 1.9-2.1 pM, the ROCK inhibitor is present at a concentration of about 2-3 pM, about 2.2-2.8 pM, or about 2.4-2.6 pM, and / or the growth factor from the TGF-P superfamily is present at a concentration of about 2-8 ng / ml, about 3-7 ng / ml or about 4-6 ng / ml. In some embodiments, in the media for culturing the second population of cells, the growth factor from the FGF family is present at a concentration of about 45-55 ng / ml, about 4654 ng / ml, about 47-53 ng / ml, about 48-52 ng / ml, or about 49-51 ng / ml, the SHH pathway inhibitor is present at a concentration of about 200-300 nM, about 220-280 nM, or about 240-260 nM, the RA signaling pathway activator is present at a concentration of about 1.7-2.3 pM, about 1.8-2.2 pM, or about 1.9-2.1 pM, the ROCK inhibitor is present at a concentration of about 2-3 pM, about 2.2-2.8 pM, or about 2.4-2.6 pM, the growth factor from the TGF-P superfamily is present at a concentration of 2 about -8 ng / ml, about 3-7 ng / ml or about 4-6 ng / ml, the PKC activator is present at a concentration of about 0.2-0.8 pM, about 0.3-0.7 pM, or about 0.4-0.6 pM, and the FoxOl inhibitor is present at a concentration of about 0.7-1.3 pM, about 0.8-1.2 pM, or about 0.9-1.1 pM, and optionally the notch signaling inhibitor is present at a concentration of about 1.7-2.3 pM, about 1.8-2.2 pM, or about 1.9-2.1 pM. In some embodiments, the PDXl-positive pancreatic progenitor cells are produced from a population of pluripotent cells. In some embodiments, the PDXl-positive pancreatic progenitor cells are produced from a population of iPS cells. In some embodiments, the PDXl-positive pancreatic progenitor cells are produced from a population of ESC cells. In some embodiments, the PDXl-positive pancreatic progenitor cells are produced from a population of definitive endoderm cells. In some embodiments, the PDXl-positive pancreatic progenitor cells are produced from a population of primitive gut tube cells. Any growth factor from the FGF family capable of inducing PDXl-positive pancreatic progenitor cells to differentiate into NKX6.1-positive pancreatic progenitor cells (e.g., alone, or with any combination of at least one SHH pathway inhibitor, a ROCK inhibitor, a growth factor from the TGF-P superfamily, and at least one retinoic acid signaling pathway activator) can be used in the method provided herein. In some embodiments, the at least one growth factor from the FGF family comprises keratinocyte growth factor (KGF). In some embodiments, the at least one growth factor from the FGF family is selected from the group consisting of FGF8B, FGF 10, and FGF21. In some examples, the method comprises contacting PDXl-positive pancreatic progenitor cells with a concentration of a growth factor from FGF family (e.g., KGF), such as, about 10 ng / mL, about 20 ng / mL, about 50 ng / mL, about 75 ng / mL, about 80 ng / mL, about 90 ng / mL, about 95 ng / mL, about 100 ng / mL, about 110 ng / mL, about 120 ng / mL, about 130 ng / mL, about 140 ng / mL, about 150 ng / mL, about 175 ng / mL, about 180 ng / mL, about 200 ng / mL, about 250 ng / mL, or about 300 ng / mL. In some examples, the method comprises contacting PDXl-positive pancreatic progenitor cells with a concentration of a growth factor from FGF family (e.g., KGF), such as, about 20-80 ng / ml, about 30-70 ng / ml, about 40-60 ng / ml, or about 45-55 ng / ml. In some examples, the method comprises contacting PDXl-positive pancreatic progenitor cells with a concentration of a growth factor from FGF family (e.g., KGF) of about 50 ng / ml. Any SHH pathway inhibitor capable of inducing PDX1-positive pancreatic progenitor cells to differentiate into NKX6.1-positive pancreatic progenitor cells (e.g., alone, or with any combination of at least one growth factor from the FGF family, a retinoic acid signaling pathway activator, ROCK inhibitor, and at least one growth factor from the TGF-P superfamily) can be used in the method provided herein. In some embodiments, the SHH pathway inhibitor comprises Santi. In some examples, the method comprises contacting PDXl-positive pancreatic progenitor cells with a concentration of a SHH pathway inhibitor (e.g., Santi), such as, about 0.001 pM, about 0.002 pM, about 0.005 pM, about 0.01 pM, about 0.02 pM, about 0.03pM, about 0.05pM, about 0.08 pM, about O.lpM, about 0.12 pM, about 0.13 pM, about 0.14 pM, about 0.15 pM, about 0.16 pM, about 0.17 pM, about 0.18 pM, about 0.19 pM, about 0.2 pM, about 0.21pM, about 0.22pM, about 0.23pM, about 0.24 pM, about 0.25 pM, about 0.26 pM, about 0.27 pM, about 0.28 pM, about 0.29 pM, about 0.3 pM, about 0.31 pM, about 0.32 pM, about 0.33 pM, about 0.34 pM, about 0.35 pM, about 0.4 pM, about 0.45 pM, about 0.5 pM, about 0.6 pM, about 0.8 pM, about 1 pM, about 2 pM, or about 5 pM. In some examples, the method comprises contacting PDXl-positive pancreatic progenitor cells with a concentration of a SHH pathway inhibitor (e.g., Santi), such as, about 220-280 nM, about 230-270 nM, about 240260 nM, or about 245-255 nM. In some examples, the method comprises contacting PDXl-positive pancreatic progenitor cells with a concentration of a SHH pathway inhibitor (e.g., Santi) of about 250 nM. Any RA signaling pathway activator capable of inducing PDXl-positive pancreatic progenitor cells to differentiate into NKX6.1-positive pancreatic progenitor cells (e.g., alone, or with any combination of at least one growth factor from the FGF family, at least one SHH pathway inhibitor, ROCK inhibitor, and at least one growth factor from the TGF-P superfamily) can be used. In some embodiments, the RA signaling pathway activator comprises retinoic acid. In some examples, the method comprises contacting PDXl-positive pancreatic progenitor cells with a concentration of an RA signaling pathway activator (e.g., retinoic acid), such as, about 0.02 pM, about O.lpM, about 0.2 pM, about 0.25 pM, about 0.3 pM, about 0.4 pM, about 0.45 pM, about 0.5 pM, about 0.55 pM, about 0.6 pM, about 0.65 pM, about 0.7 pM, about 0.75 pM, about 0.8 pM, about 0.85 pM, about 0.9 pM, about 1 pM, about 1.1 pM, about 1.2 pM, about 1.3 pM, about 1.4 pM, about 1.5 pM, about 1.6 pM, about 1.7 pM, about 1.8 pM, about 1.9 pM, about 2 pM, about 2.1 pM, about 2.2 pM, about 2.3 pM, about 2.4 pM, about 2.5 pM, about 2.6 pM, about 2.7 pM, about 2.8 pM, about 3 pM, about 3.2 pM, about 3.4 pM, about 3.6 pM, about 3.8 pM, about 4 pM, about 4.2 pM, about 4.4 pM, about 4.6 pM, about 4.8 pM, about 5 pM, about 5.5 pM, about 6 |aM, about 6.5 |aM, about 7 |aM, about 7.5 |aM, about 8 |aM, about 8.5 |jM, about 9 |aM, about 9.5 |aM, about 10 |aM, about 12 |aM, about 14 |aM, about 15 |aM, about 16 |jM, about 18 |aM, about 20 |aM, about 50 |aM, or about 100 |aM. In some examples, the method comprises contacting PDX1-positive pancreatic progenitor cells with a concentration of an RA signaling pathway activator (e.g., retinoic acid), such as, about 70-130 nM, about 80120 nM, about 90-110 nM, or about 95-105 nM. In some examples, the method comprises contacting PDX1-positive pancreatic progenitor cells with a concentration of an RA signaling pathway activator (e.g., retinoic acid) of about 100 nM. Any ROCK inhibitor capable of inducing PDX1-positive pancreatic progenitor cells to differentiate into NKX6.1-positive pancreatic progenitor cells (e.g., alone, or with any combination of at least one growth factor from the FGF family, at least one SHH pathway inhibitor, a RA signaling pathway activator, and at least one growth factor from the TGF-P superfamily) can be used. In some embodiments, the ROCK inhibitor comprises Thiazovivin, Y-27632, Fasudil / HA1077, or 14-1152. In some examples, the method comprises contacting PDX1-positive pancreatic progenitor cells with a concentration of a ROCK inhibitor (e.g., Y-27632 or Thiazovivin), such as, about 0.2 pM, about 0.5 pM, about 0.75 pM, about 1 pM, about 2 pM, about 3 pM, about 4 pM, about 5 pM, about 6 pM, about 7 pM, about 7.5 pM, about 8 pM, about 9 pM, about 10 pM, about 11 pM, about 12 pM, about 13 pM, about 14 pM, about 15 pM, about 16 pM, about 17 pM, about 18 pM, about 19 pM, about 20 pM, about 21 pM, about 22 pM, about 23 pM, about 24 pM, about 25 pM, about 26 pM, about 27 pM, about 28 pM, about 29 pM, about 30 pM, about 35 pM, about 40 pM, about 50 pM, or about 100 pM. In some examples, the method comprises contacting PDX1-positive pancreatic progenitor cells with a concentration of a ROCK inhibitor (e.g., Y-27632 or Thiazovivin), such as, about 2.2-2.8 pM, about 2.3-2.7 pM, or about 2.4-2.6 pM. In some examples, the method comprises contacting PDX1-positive pancreatic progenitor cells with a concentration of a ROCK inhibitor (e.g., Y-27632 or Thiazovivin) of about 2.5 pM. Any activator from the TGF-P superfamily capable of inducing PDX1-positive pancreatic progenitor cells to differentiate into NKX6.1-positive pancreatic progenitor cells (e.g., alone, or with any combination of at least one growth factor from the FGF family, at least one SHH pathway inhibitor, a RA signaling pathway activator, and ROCK inhibitor) can be used. In some embodiments, the activator from the TGF-P superfamily comprises Activin A or GDF8. In some examples, the method comprises contacting PDX1-positive pancreatic progenitor cells with a concentration of a growth factor from TGF-P superfamily (e.g., Activin A), such as, about 0.1 ng / mL, about 0.2 ng / mL, about 0.3 ng / mL, about 0.4 ng / mL, about 0.5 ng / mL, about 0.6 ng / mL, about 0.7 ng / mL, about 0.8 ng / mL, about 1 ng / mL, about 1.2 ng / mL, about 1.4 ng / mL, about 1.6 ng / mL, about 1.8 ng / mL, about 2 ng / mL, about 2.2 ng / mL, about 2.4 ng / mL, about 2.6 ng / mL, about 2.8 ng / mL, about 3 ng / mL, about 3.2 ng / mL, about 3.4 ng / mL, about 3.6 ng / mL, about 3.8 ng / mL, about 4 ng / mL, about 4.2 ng / mL, about 4.4 ng / mL, about 4.6 ng / mL, about 4.8 ng / mL, about 5 ng / mL, about 5.2 ng / mL, about 5.4 ng / mL, about 5.6 ng / mL, about 5.8 ng / mL, about 6 ng / mL, about 6.2 ng / mL, about 6.4 ng / mL, about 6.6 ng / mL, about 6.8 ng / mL, about 7 ng / mL, about 8 ng / mL, about 9 ng / mL, about 10 ng / mL, about 20 ng / mL, about 30 ng / mL, or about 50 ng / mL. In some examples, the method comprises contacting PDX1-positive pancreatic progenitor cells with a concentration of a growth factor from TGF-P superfamily (e.g., Activin A), such as, about 2-8 ng / ml, about 3-7 ng / ml, about 4-6 ng / ml, or about 4.5-5.5 ng / ml. In some examples, the method comprises contacting PDX1-positive pancreatic progenitor cells with a concentration of a growth factor from TGF-P superfamily (e.g., Activin A), such as, about 5 ng / mL. Any FoxOl inhibitor capable of inducing PDX1-positive pancreatic progenitor cells to differentiate into NKX6.1-positive pancreatic progenitor cells (e.g., alone, or with any combination of at least one growth factor from the FGF family, at least one retinoic acid signaling pathway activator, ROCK inhibitor, at least one growth factor from the TGF-P superfamily, PKC activator, and Notch signaling inhibitor) can be used in the method provided herein. In some embodiments, the FoxOl inhibitor is AS 1842856. In some examples, the method comprises contacting PDX1-positive pancreatic progenitor cells with a concentration of a FoxOl inhibitor (e.g., AS1842856), such as, about O.lpM, about 0.12 pM, about 0.13 pM, about 0.14 pM, about 0.15 pM, about 0.16 pM, about 0.17 pM, about 0.18 pM, about 0.19 pM, about 0.2 pM, about 0.21pM, about 0.22pM, about 0.23pM, about 0.24 pM, about 0.25 pM, about 0.26 pM, about 0.27 pM, about 0.28 pM, about 0.29 pM, about 0.3 pM, about 0.31 pM, about 0.32 pM, about 0.33 pM, about 0.34 pM, about 0.35 pM, about 0.4 pM, about 0.45 pM, about 0.5 pM, about 0.6 pM, about 0.8 pM, about 1 pM, about 2 pM, or about 5 pM. In some examples, the method comprises contacting PDX1-positive pancreatic progenitor cells with a concentration of a FoxOl inhibitor (e.g., AS1842856), such as, about 0.7-1.3 pM, about 0.8-1.2 pM, about or 0.9-1.1 pM. In some examples, the method comprises contacting PDXl-positive pancreatic progenitor cells with a concentration of a FoxOl inhibitor (e.g., AS 1842856), such as, about 1 pM. Any PKC activator capable of inducing PDXl-positive pancreatic progenitor cells to differentiate into NKX6.1-positive pancreatic progenitor cells (e.g., alone, or with any combination of at least one growth factor from the FGF family, at least one retinoic acid signaling pathway activator, ROCK inhibitor, at least one growth factor from the TGF-P superfamily, FoxOl inhibitor, and Notch signaling inhibitor) can be used in the method provided herein. In some embodiments, the PKC activator is PDBU. In some examples, the method comprises contacting PDX1-positive pancreatic progenitor cells with a concentration of a PKC activator (e.g., PDBU), such as, about O.lpM, about 0.12 pM, about 0.13 pM, about 0.14 pM, about 0.15 pM, about 0.16 pM, about 0.17 pM, about 0.18 pM, about 0.19 pM, about 0.2 pM, about 0.21pM, about 0.22pM, about 0.23pM, about 0.24 pM, about 0.25 pM, about 0.26 pM, about 0.27 pM, about 0.28 pM, about 0.29 pM, about 0.3 pM, about 0.31 pM, about 0.32 pM, about 0.33 pM, about 0.34 pM, about 0.35 pM, about 0.4 pM, about 0.45 pM, about 0.5 pM, about 0.6 pM, about 0.8 pM, about 1 pM, about 2 pM, or about 5 pM. In some examples, the method comprises contacting PDX1-positive pancreatic progenitor cells with a concentration of a PKC activator (e.g., PDBU), such as, about 0.2-0.8 pM, about 0.3-0.7 pM, about 0.4-0.6 pM. In some examples, the method comprises contacting PDX1-positive pancreatic progenitor cells with a concentration of a PKC activator (e.g., PDBU), such as, about 0.5 pM. Any Notch signaling inhibitor capable of inducing PDX1-positive pancreatic progenitor cells to differentiate into NKX6.1-positive pancreatic progenitor cells (e.g., alone, or with any combination of at least one growth factor from the FGF family, at least one retinoic acid signaling pathway activator, ROCK inhibitor, at least one growth factor from the TGF-P superfamily, FoxOl inhibitor, and PKC activator) can be used in the method provided herein. In some embodiments, the Notch signaling inhibitor is XXI. In some examples, the method comprises contacting PDX1-positive pancreatic progenitor cells with a concentration of a Notch signaling inhibitor (e.g., XXI), such as, about O.lpM, about 0.12 pM, about 0.13 pM, about 0.14 pM, about 0.15 pM, about 0.16 pM, about 0.17 pM, about 0.18 pM, about 0.19 pM, about 0.2 pM, about 0.21 pM, about 0.22 pM, about 0.23 pM, about 0.24 pM, about 0.25 pM, about 0.26 pM, about 0.27 pM, about 0.28 pM, about 0.29 pM, about 0.3 pM, about 0.31 pM, about 0.32 pM, about 0.33 pM, about 0.34 pM, about 0.35 pM, about 0.4 pM, about 0.45 pM, about 0.5 pM, about 0.6 pM, about 0.8 pM, about 1 pM, about 2 pM, or about 5 pM. In some examples, the method comprises contacting PDX1-positive pancreatic progenitor cells with a concentration of a Notch signaling inhibitor (e.g., XXI), such as, about 1.7-2.3 pM, about 1.8-2.2 pM, or about 1.9- 2.1 pM. In some examples, the method comprises contacting PDXl-positive pancreatic progenitor cells with a concentration of a Notch signaling inhibitor (e.g., XXI), such as, about 2 pM. In some embodiments, the cells are further contacted with a water-soluble synthetic polymer. In some embodiments, the water-soluble synthetic polymer is polyvinyl alcohol. In some cases, the polyvinyl alcohol is at least 78% hydrolyzed, e.g., 79-81% hydrolyzed, 87-89% hydrolyzed, 87-90% hydrolyzed, or 99% hydrolyzed. In some embodiments, the polyvinyl alcohol (PVA) is 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% hydrolyzed. In some embodiments, the PVA is 80% hydrolyzed. In some embodiments, the PDX1-positive, NKX6.1-positive pancreatic progenitor cells are obtained by contacting PDX1-positive pancreatic progenitor cells under conditions that promote cell clustering with KGF, Santi, and RA, for a period of 5 days or 6 days. In some embodiments, the PDX1-positive, NKX6.1-positive pancreatic progenitor cells are obtained by contacting PDX1-positive pancreatic progenitor cells under conditions that promote cell clustering with KGF, Santi, RA, thiazovivin, and Activin A, for a period of 5 or 6 days. In some embodiments, the PDX1-positive, NKX6.1-positive pancreatic progenitor cells are obtained by contacting PDX1-positive pancreatic progenitor cells under conditions that promote cell clustering with KGF for a period of 5 days. In some embodiments, the PDX1-positive, NKX6.1-positive pancreatic progenitor cells are obtained by contacting PDX1-positive pancreatic progenitor cells under conditions that promote cell clustering with KGF for a period of 6 days. In some embodiments, the PDX1-positive, NKX6.1-positive pancreatic progenitor cells are obtained by: a) contacting PDXl-positive pancreatic progenitor cells with KGF, Santi, RA, thiazovivin, and Activin A, for a period of 3, 4 or 5 days (e.g., 4 days), followed by; b) contacting the cells of a) with PDBU, XXI, KGF, Santi, RA, thiazovivin, and Activin A and optionally AS 1842856 for a period of 1, 2 or 3 days (e.g., 2 days). Insulin-positive Endocrine Cells Aspects of the disclosure involve insulin-positive endocrine cells (e.g., NKX6.1-positive, ISL1-positive cells, or P-like cells) and additional methods of generating insulinpositive endocrine cells. Insulin-positive endocrine cells of use herein can be derived from any source or generated in accordance with any suitable protocol. In some aspects, NKX6.1-positive pancreatic progenitor cells are differentiated to insulin-positive endocrine cells (e.g., NKX6.1-positive, ISLl-positive cells, or P-like cells), In some aspects, the insulin-positive endocrine cells are further differentiated, e.g., by induction or maturation to SC-P cells. In some aspects, a method of producing an insulin-positive endocrine cell from an NKX6.1-positive pancreatic progenitor cell comprises contacting a population of cells (e.g., under conditions that promote cell clustering) comprising NKX6-l-positive pancreatic progenitor cells with a) a TGF-P signaling pathway inhibitor, b) a thyroid hormone signaling pathway activator,, c) a BMP pathway inhibitor, and / or d) a protein kinase inhibitor to induce the differentiation of at least one NKX6.1-positive pancreatic progenitor cell in the population into an insulin-positive endocrine cell, wherein the insulin-positive endocrine ceil expresses insulin. In some embodiments, insulin-positive endocrine cells express PDX1, NKX6.1, ISL1, NKX2.2, Mafb, glis3, Suri, Kir6.2, Znt8, SLC2A1, SLC2A3 and / or insulin. Any TGF-P signaling pathway inhibitor capable of inducing the differentiation of NKX6.1-positive pancreatic progenitor cells to differentiate into insulin-positive endocrine cells (e.g., alone, or in combination with other P cell-differentiation factors, e.g., a thyroid hormone signaling pathway activator) can be used. In some embodiments, the TGF-P signaling pathway comprises TGF-P receptor type I kinase signaling. In some embodiments, the TGF-P signaling pathway inhibitor comprises Alk5 inhibitor II. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of a TGF-P signaling pathway inhibitor (e.g., Alk5 inhibitor such as Alk5 inhibitor II), such as, about 0.1 pM, about 0.5 pM, about 1 pM, about 1.5 pM, about 2 pM, about 2.5 pM, about 3 pM, about 3.5 pM, about 4 pM, about 4.5 pM, about 5 pM, about 5.5 pM, about 6 pM, about 6.5 pM, about 7 pM, about 7.5 pM, about 8 pM, about 8.5 pM, about 9 pM, about 9.5 pM, about 10 pM, about 10.5 pM, about 11 pM, about 11.5 pM, about 12 pM, about 12.5 pM, about 13 pM, about 13.5 pM, about 14 pM, about 14.5 pM, about 15 pM, about 15.5 pM, about 16 pM, about 16.5 pM, about 17 pM, about 17.5 pM, about 18 pM, about 18.5pM, about 19 pM, about 19.5 pM, about 20 pM, about 25 pM, about 30 pM, about 35 pM, about 40 pM, about 45 pM, or about 50 pM. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of a TGF-P signaling pathway inhibitor (e.g., Alk5 inhibitor such as Alk5 inhibitor II), such as, about 7-13 pM, about 8-12 pM, about 9-11 pM. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of a TGF-P signaling pathway inhibitor (e.g., Alk5 inhibitor such as Alk5 inhibitor II), such as, about 10 pM. Any thyroid hormone signaling pathway activator capable of inducing the differentiation of NKX6.1-positive pancreatic progenitor cells to differentiate into insulinpositive endocrine cells (e.g., alone, or in combination with other P cell-differentiation factors, e.g., a TGF-P signaling pathway inhibitor) can be used. In some embodiments, the thyroid hormone signaling pathway activator comprises triiodothyronine (T3). In some embodiments, the thyroid hormone signaling pathway activator comprises GC-1. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of thyroid hormone signaling pathway activator (e.g., GC-1), such as, about O.lpM, about 0.12 pM, about 0.13 pM, about 0.14 pM, about 0.15 pM, about 0.16 pM, about 0.17 pM, about 0.18 pM, about 0.19 pM, about 0.2 pM, about 0.21pM, about 0.22pM, about 0.23pM, about 0.24 pM, about 0.25 pM, about 0.26 pM, about 0.27 pM, about 0.28 pM, about 0.29 pM, about 0.3 pM, about 0.31 pM, about 0.32 pM, about 0.33 pM, about 0.34 pM, about 0.35 pM, about 0.4 pM, about 0.45 pM, about 0.5 pM, about 0.6 pM, about 0.8 pM, about 1 pM, about 2 pM, or about 5 pM. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of thyroid hormone signaling pathway activator (e.g., GC-1), such as, about 0.7-1.3 pM, about 0.8-1.2 pM, or about 0.9-1.1 pM. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of thyroid hormone signaling pathway activator (e.g., GC-1), such as, about 1 pM. In some embodiments, the method comprises contacting the population of cells (e.g., NKX6.1-positive pancreatic progenitor cells) with at least one additional factor. In some embodiments, the method comprises contacting the PDX1-positive NKX6.1-positive pancreatic progenitor cells with at least one of i) a SHH pathway inhibitor, ii) a y-secretase inhibitor, iii) at least one growth factor from the epidermal growth factor (EGF) family, iv) a TGF-P signaling pathway inhibitor, or vii) a thyroid hormone signaling pathway activator. In some embodiments, the method comprises contacting the population of cells (e.g., NKX6.1-positive pancreatic progenitor cells) with at least one additional factor. In some embodiments, the method comprises contacting the PDXl-positive NKX6.1-positive pancreatic progenitor cells with at least one of i) a SHH pathway inhibitor, ii) a RA signaling pathway activator, iii) a y-secretase inhibitor, iv) at least one growth factor from the epidermal growth factor (EGF) family, v) a protein kinase inhibitor, vi) a TGF-P signaling pathway inhibitor, vii) a thyroid hormone signaling pathway activator, viii) a wnt signaling pathway inhibitor, or ix) a PKC activator. In some embodiments, the method comprises contacting the PDXl-positive NKX6.1-positive pancreatic progenitor cells with at least one of i) a SHH pathway inhibitor, ii) a RA signaling pathway activator, iii) a y-secretase inhibitor, iv) at least one growth factor from the epidermal growth factor (EGF) family, v) at least one bone morphogenetic protein (BMP) signaling pathway inhibitor, vi) a TGF-P signaling pathway inhibitor, vii) a thyroid hormone signaling pathway activator, viii) a protein kinase inhibitor, or ix) a ROCK inhibitor. In some embodiments, the method comprises contacting the PDXl-positive NKX6.1-positive pancreatic progenitor cells with at least one of i) a SHH pathway inhibitor, ii) a RA signaling pathway activator, iii) a y-secretase inhibitor, iv) at least one growth factor from the epidermal growth factor (EGF) family, v) at least one bone morphogenetic protein (BMP) signaling pathway inhibitor, vi) a TGF-P signaling pathway inhibitor, vii) a thyroid hormone signaling pathway activator, viii) an epigenetic modifying compound, ix) a protein kinase inhibitor, or x) a ROCK inhibitor. In some embodiments, the method comprises contacting the PDXl-positive, NKX6.1-positive pancreatic progenitor cells in a culture with a i) a SHH pathway inhibitor, ii) a RA signaling pathway activator, iii) a y-secretase inhibitor, iv) at least one growth factor from the epidermal growth factor (EGF) family, v) at least one bone morphogenetic protein (BMP) signaling pathway inhibitor, vi) a TGF-P signaling pathway inhibitor, vii) a thyroid hormone signaling pathway activator, viii) an epigenetic modifying compound, ix) a protein kinase inhibitor, x) a ROCK inhibitor, xi) a PKC activator and xii) a Wnt signaling pathway inhibitor for 1, 2, or 3 days (e.g., 1-2, 1-3, or 2-3 days), and then contacting the cells in the culture with i) a y-secretase inhibitor, ii) at least one growth factor from the epidermal growth factor (EGF) family, iii) at least one bone morphogenetic protein (BMP) signaling pathway inhibitor, iv) a TGF-P signaling pathway inhibitor, v) a thyroid hormone signaling pathway activator, vi) an epigenetic modifying compound, vii) a protein kinase inhibitor, and viii) a ROCK inhibitor for a period of 1, 2, 3, 4, 5, 6, or 7 days (e.g., 1-7, 15, 1-3, 3-7, 3-5, 5-7, or 4-6 days) in the absence of a SHH pathway inhibitor, a RA signaling pathway activator, a Wnt signaling pathway inhibitor, PKC activator, and / or growth factor from the epidermal growth factor (EGF) family. In some embodiments, in the method of generating the insulin-positive endocrine cells from the PDXl-positive NKX6.1-po stive pancreatic progenitor cells, some of the differentiation factors are present only for the first 1, 2, 3, 4, or 5 days during the differentiation step. In some embodiments, some of the differentiation factors, such as the SHH pathway inhibitor, the RA signaling pathway activator, the PKC activator, and the at least one growth factor from the EGF family are removed from the culture medium after the first 1, 2, or 3 days of incubation. Any y-secretase inhibitor that is capable of inducing the differentiation of NKX6.1-positive pancreatic progenitor cells in a population into insulin-positive endocrine cells (e.g., alone, or in combination with any of a TGF-P signaling pathway inhibitor and / or a thyroid hormone signaling pathway activator) can be used. In some embodiments, the y-secretase inhibitor comprises XXI. In some embodiments, the y-secretase inhibitor comprises DAPT. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of a y-secretase inhibitor (e.g., XXI), such as, about 0.01 pM, about 0.02 pM, about 0.05 pM, about 0.075 pM, about 0.1 pM, about 0.2 pM, about 0.3 pM, about 0.4 pM, about 0.5 pM, about 0.6 pM, about 0.7 pM, about 0.8 pM, about 0.9 pM, about 1 pM, about 1.1 pM, about 1.2 pM, about 1.3 pM, about 1.4 pM, about 1.5 pM, about 1.6 pM, about 1.7 pM, about 1.8 pM, about 1.9 pM, about 2 pM, about 2.1 pM, about 2.2 pM, about 2.3 pM, about 2.4 pM, about 2.5 pM, about 2.6 pM, about 2.7 pM, about 2.8 pM, about 2.9 pM, about 3 pM, about 3.2 pM, about 3.4 pM, about 3.6 pM, about 3.8 pM, about 4 pM, about 4.2 pM, about 4.4 pM, about 4.6 pM, about 4.8 pM, about 5 pM, about 5.2 pM, about 5.4 pM, about 5.6 pM, about 5.8 pM, about 6 pM, about 6.2 pM, about 6.4 pM, about 6.6 pM, about 6.8 pM, about 7 pM, about 8 pM, about 9 pM, about 10 pM, about 20 pM, about 30 pM, or about 50 pM. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of a y-secretase inhibitor (e.g., XXI), such as, about 1.7-2.3 pM, about 1.82.2 pM, or about 1.9-2.1 pM. In some examples, the method comprises contacting NKX6.1- positive pancreatic progenitor cells with a concentration of a y-secretase inhibitor (e.g., XXI), such as about 2 pM. Any growth factor from the EGF family capable of inducing the differentiation of NKX6.1-positive pancreatic progenitor cells in a population into insulin-positive endocrine cells (e.g., alone, or in combination with any of a TGF-P signaling pathway inhibitor and / or a thyroid hormone signaling pathway activator) can be used. In some embodiments, the at least one growth factor from the EGF family comprises betacellulin. In some embodiments, at least one growth factor from the EGF family comprises EGF. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of a growth factor from EGF family (e.g., betacellulin), such as, about 1 ng / mL, about 2 ng / mL, about 4 ng / mL, about 6 ng / mL, about 8 ng / mL, about 10 ng / mL, about 12 ng / mL, about 14 ng / mL, about 16 ng / mL, about 18 ng / mL, about 20 ng / mL, about 22 ng / mL, about 24 ng / mL, about 26 ng / mL, about 28 ng / mL, about 30 ng / mL, about 40 ng / mL, about 50 ng / mL, about 75 ng / mL, about 80 ng / mL, about 90 ng / mL, about 95 ng / mL, about 100 ng / mL, about 150 ng / mL, about 200 ng / mL, about 250 ng / mL, or about 300 ng / mL. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of a growth factor from EGF family (e.g., betacellulin), such as, about 17-23 ng / ml, about 18-22 ng / ml, or about 19-21 ng / ml. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of a growth factor from EGF family (e.g., betacellulin), such as, about 20 ng / ml. Any RA signaling pathway activator capable of inducing the differentiation of NKX6.1-positive pancreatic progenitor cells to differentiate into insulin-positive endocrine cells (e.g., alone, or in combination with any of a TGF-P signaling pathway inhibitor and / or a thyroid hormone signaling pathway activator) can be used. In some embodiments, the RA signaling pathway activator comprises RA. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of an RA signaling pathway activator (e.g., retinoic acid), such as, about 0.02 pM, about 0.05 pM, about 0.1 pM, about 0.2 pM, about 0.25 pM, about 0.3 pM, about 0.4 pM, about 0.45 pM, about 0.5 pM, about 0.55 pM, about 0.6 pM, about 0.65 pM, about 0.7 pM, about 0.75 pM, about 0.8 pM, about 0.85 pM, about 0.9 pM, about 1 pM, about 1.1 pM, about 1.2 pM, about 1.3 pM, about 1.4 pM, about 1.5 pM, about 1.6 pM, about 1.7 pM, about 1.8 pM, about 1.9 pM, about 2 pM, about 2.1 pM, about 2.2 pM, about 2.3 pM, about 2.4 pM, about 2.5 pM, about 2.6 pM, about 2.7 pM, about 2.8 pM, about 3 pM, about 3.2 pM, about 3.4 pM, about 3.6 pM, about 3.8 pM, about 4 pM, about 4.2 pM, about 4.4 pM, about 4.6 pM, about 4.8 pM, about 5 pM, about 5.5 pM, about 6 pM, about 6.5 pM, about 7 pM, about 7.5 pM, about 8 pM, about 8.5 pM, about 9 pM, about 9.5 pM, about 10 pM, about 12 pM, about 14 |aM, about 15 |aM, about 16 |aM, about 18 |aM, about 20 |aM, about 50 |jM, or about 100 |aM. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of an RA signaling pathway activator (e.g., retinoic acid), such as, about 20-80 nM, about 30-70 nM, or about 40-60 nM. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of an RA signaling pathway activator (e.g., retinoic acid), such as, about 50 nM. Any SHH pathway inhibitor capable of inducing the differentiation of NKX6.1-positive pancreatic progenitor cells to differentiate into insulin-positive endocrine cells (e.g., alone, or in combination with any of a TGF-P signaling pathway inhibitor and / or a thyroid hormone signaling pathway activator) can be used in the method provided herein. In some embodiments, the SHH pathway inhibitor comprises Santi. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of a SHH pathway inhibitor (e.g., Santi), such as, about 0.001 pM, about 0.002 pM, about 0.005 pM, about 0.01 pM, about 0.02 pM, about 0.03pM, about 0.05pM, about 0.08 pM, about O.lpM, about 0.12 pM, about 0.13 pM, about 0.14 pM, about 0.15 pM, about 0.16 pM, about 0.17 pM, about 0.18 pM, about 0.19 pM, about 0.2 pM, about 0.21pM, about 0.22pM, about 0.23pM, about 0.24 pM, about 0.25 pM, about 0.26 pM, about 0.27 pM, about 0.28 pM, about 0.29 pM, about 0.3 pM, about 0.31 pM, about 0.32 pM, about 0.33 pM, about 0.34 pM, about 0.35 pM, about 0.4 pM, about 0.45 pM, about 0.5 pM, about 0.6 pM, about 0.8 pM, about 1 pM, about 2 pM, or about 5 pM. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of a SHH pathway inhibitor (e.g., Santi), such as, about 220-280 nM, about 230-270 nM, about 240-260 nM, or about 245-255 nM. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of a SHH pathway inhibitor (e.g., Santi), such as, about 250 nM. Any BMP signaling pathway inhibitor capable of inducing the differentiation of NKX6.1-positive pancreatic progenitor cells to differentiate into insulin-positive endocrine cells (e.g., alone, or in combination with any of a TGF-P signaling pathway inhibitor and / or a thyroid hormone signaling pathway activator) can be used. In some embodiments, the BMP signaling pathway inhibitor comprises LDN193189 or DMH-1. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of BMP signaling pathway inhibitor (e.g., LDN1931189), such as, about 30 nM, about 40 nM, about 50 nM, about 60 nM, about 70 nM, about 80 nM, about 90 nM, about 100 nM, about 110 nM, about 120 nM, about 130 nM, about 140 nM, about 150 nM, about 160 nM, about 170 nM, about 180 nM, about 190 nM, about 200 nM, about 210 nM, about 220 nM, about 230 nM, about 240 nM, about 250 nM, about 280 nM, about 300 nM, about 400 nM, about 500 nM, or about IpM. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of BMP signaling pathway inhibitor (e.g., LDN1931189), such as, about 70-130 nM, about 80-120 nM, about 90-110 nM. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of BMP signaling pathway inhibitor (e.g., LDN1931189), such as, about 100 nM. Any ROCK inhibitor that is capable of inducing the differentiation of NKX6.1-positive pancreatic progenitor cells in a population into insulin-positive endocrine cells (e.g., alone, or in combination with any of a TGF-0 signaling pathway inhibitor and / or a thyroid hormone signaling pathway activator) can be used. In some embodiments, the ROCK inhibitor comprises Thiazovivin, Y-27632, Fasudil / HA1077, or H-l152. In some embodiments, the ROCK inhibitor comprises Y-27632. In some embodiments, the ROCK inhibitor comprises Thiazovivin. In some examples, the method comprises contacting PDX1-positive, NKX6.1-positive pancreatic progenitor cells with a concentration of a ROCK inhibitor (e.g., Y-27632 or Thiazovivin), such as, about 0.2 pM, about 0.5 pM, about 0.75 pM, about 1 pM, about 2 pM, about 3 pM, about 4 pM, about 5 pM, about 6 pM, about 7 pM, about 7.5 pM, about 8 pM, about 9 pM, about 10 pM, about 11 pM, about 12 pM, about 13 pM, about 14 pM, about 15 pM, about 16 pM, about 17 pM, about 18 pM, about 19 pM, about 20 pM, about 21 pM, about 22 pM, about 23 pM, about 24 pM, about 25 pM, about 26 pM, about 27 pM, about 28 pM, about 29 pM, about 30 pM, about 35 pM, about 40 pM, about 50 pM, or about 100 pM. In some embodiments, the ROCK inhibitor comprises Thiazovivin. In some examples, the method comprises contacting PDX1-positive, NKX6.1-positive pancreatic progenitor cells with a concentration of a ROCK inhibitor (e.g., Y-27632 or Thiazovivin), such as, about 2.2-2.8 pM, about 2.3-2.7 pM, or about 2.4-2.6 pM. In some embodiments, the ROCK inhibitor comprises Thiazovivin. In some examples, the method comprises contacting PDX1-positive, NKX6.1-positive pancreatic progenitor cells with a concentration of a ROCK inhibitor (e.g., Y-27632 or Thiazovivin), such as, about 2.5 pM. Any epigenetic modifying compound that is capable of inducing the differentiation of NKX6.1-positive pancreatic progenitor cells in a population into insulin-positive endocrine cells (e.g., alone, or in combination with any of a TGF-P signaling pathway inhibitor and / or a thyroid hormone signaling pathway activator) can be used. In some embodiments, the epigenetic modifying compound comprises a histone methyltransferase inhibitor or a HD AC inhibitor. In some embodiments, the epigenetic modifying compound comprises a histone methyltransferase inhibitor, e.g., DZNep. In some embodiments, the epigenetic modifying compound comprises a HD AC inhibitor, e.g., KD5170. In some examples, the method comprises contacting PDX1-positive, NKX6.1-positive pancreatic progenitor cells with a concentration of an epigenetic modifying compound (e.g., DZNep or KD5170), such as, about 0.01 pM, about 0.025 pM, about 0.05 pM, about 0.075 pM, about 0.1 pM, about 0.15 pM, about 0.2 pM, about 0.5 pM, about 0.75 pM, about 1 pM, about 2 pM, about 3 pM, about 4 pM, about 5 pM, about 6 pM, about 7 pM, about 7.5 pM, about 8 pM, about 9 pM, about 10 pM, about 15 pM, about 20 pM, about 25 pM, about 30 pM, about 35 pM, about 40 pM, about 50 pM, or about 100 pM. In some examples, the method comprises contacting PDX1-positive, NKX6.1-positive pancreatic progenitor cells with a concentration of an epigenetic modifying compound (e.g., DZNep or KD5170), such as, about 70-130 nM, about 80-120 nM, or about 90-110 nM. In some examples, the method comprises contacting PDX1-positive, NKX6.1-positive pancreatic progenitor cells with a concentration of an epigenetic modifying compound (e.g., DZNep or KD5170), such as, about 100 nM. Any Wnt signaling pathway inhibitor that is capable of inducing the differentiation of NKX6.1-positive pancreatic progenitor cells in a population into insulin-positive endocrine cells (e.g., alone, or in combination with any of a TGF-P signaling pathway inhibitor and / or a thyroid hormone signaling pathway activator) can be used. In some embodiments, the Wnt signaling pathway inhibitor comprises a tankyrase inhibitor. In some embodiments, the tankyrase inhibitor is NVP-TNKS656. In some examples, the method comprises contacting PDX1-positive, NKX6.1-positive pancreatic progenitor cells with a concentration of a Wnt signaling pathway inhibitor (e.g., a tankyrase inhibitor such as NVP-TNKS656), such as, about O.lpM, about 0.15 pM, about 0.2 pM, about 0.25 pM, about 0.3 pM, about 0.35 pM, about 0.4 pM, about 0.45 pM, about 0.5 pM, about 0.55 pM, about 0.6 pM, about 0.65 pM, about 0.7 pM, about 0.75 pM, about 0.8 pM, about 0.85 pM, about 0.9 pM, about 0.95 pM, about 1 pM, about 1.5 pM, about 2 pM, about 2.5 pM, about 3 pM, about 3.5 pM, about 4 pM, about 4.5 pM, or about 5 pM. In some examples, the method comprises contacting PDX1-positive, NKX6.1-positive pancreatic progenitor cells with a concentration of a Wnt signaling pathway inhibitor (e.g., a tankyrase inhibitor such as NVP-TNKS656), such as, about 1.7-2.3 pM, about 1.8-2.2 pM, or about 1.9-2.1 pM. In some examples, the method comprises contacting PDX1-positive, NKX6.1-positive pancreatic progenitor cells with a concentration of a Wnt signaling pathway inhibitor (e.g., a tankyrase inhibitor such as NVP-TNKS656), such as, about 2 pM. Any PKC activator that is capable of inducing the differentiation of NKX6.1-positive pancreatic progenitor cells in a population into insulin-positive endocrine cells (e.g., alone, or in combination with any of a TGF-P signaling pathway inhibitor and / or a thyroid hormone signaling pathway activator) can be used. In some embodiments, the PKC activator is TPB or PDBU. In some examples, the method comprises contacting PDX1-positive, NKX6.1-positive pancreatic progenitor cells with a concentration of a PKC activator (TPB or PDBU), such as, about 0.01 pM, about 0.025 |aM, about 0.05 |aM, about 0.075 |aM, about 0.1 |aM, about 0.15 |aM, about 0.2 |jM, about 0.25 |aM, about 0.3 |aM, about 0.35 |aM, about 0.4 |aM, about 0.45 |aM, about 0.5 |jM, about 0.55 |aM, about 0.6 |aM, about 0.65 |aM, about 0.7 |aM, about 0.75 |aM, about 0.8 |jM, about 0.85 |aM, about 0.9 |aM, about 0.95 |aM, about 1 |aM, about 2 |aM, about 3 |jM, about 4 |aM, about 5 |aM, about 6 |aM, about 7 |aM, about 7.5 |aM, about 8 |aM, about 9 |aM, about 10 |jM, about 15 |aM, or about 20 |aM. In some examples, the method comprises contacting PDX1-positive, NKX6.1-positive pancreatic progenitor cells with a concentration of a PKC activator (TPB or PDBU), such as, about 450-550 mM, about 475-525 nM, about 490-510 nM, or about 495-505 nM. In some examples, the method comprises contacting PDX1-positive, NKX6.1-positive pancreatic progenitor cells with a concentration of a PKC activator (TPB or PDBU), such as, about 500 nM. In some embodiments, the population of cells is optionally contacted with a protein kinase inhibitor. In some embodiments, the population of cells is not contacted with the protein kinase inhibitor. In some embodiments, the population of cells is contacted with the protein kinase inhibitor. Any protein kinase inhibitor that is capable of inducing the differentiation of NKX6.1-positive pancreatic progenitor cells in a population into insulin-positive endocrine cells (e.g., alone, or in combination with any of a TGF-P signaling pathway inhibitor and / or a thyroid hormone signaling pathway activator). In some embodiments, the protein kinase inhibitor comprises staurosporine. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of a protein kinase inhibitor (e.g., staurosporine), such as, about 0.1 nM, about 0.2 nM, about 0.3 nM, about 0.4 nM, about 0.5 nM, about 0.6 nM, about 0.7 nM, about 0.8 nM, about 0.9 nM, about 1 nM, about 1.1 nM, about 1.2 nM, about 1.3 nM, about 1.4 nM, about 1.5 nM, about 1.6 nM, about 1.7 nM, about 1.8 nM, about 1.9 nM, about 2.0 nM, about 2.1 nM, about 2.2 nM, about 2.3 nM, about 2.4 nM, about 2.5 nM, about 2.6 nM, about 2.7 nM, about 2.8 pM, about 2.9 nM, about 3 nM, about 3.1 nM, about 3.2 nM, about 3.3 nM, about 3.4 nM, about 3.5 nM, about 3.6 nM, about 3.7 nM, about 3.8 nM, about 3.9 nM, about 4.0 nM, about 4.1 nM, about 4.2 nM, about 4.3 nM, about 4.4 nM, about 4.5 nM, about 4.6 nM, about 4.7 nM, about 4.8 pM, about 4.9 nM, or about 5 nM. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of a protein kinase inhibitor (e.g., staurosporine), such as, about 1-5 nM, about 2-4 nM, or about 2.53.5 nM. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of a protein kinase inhibitor (e.g., staurosporine), such as, about 3 nM. In some embodiments, the cells are further contacted with a water-soluble synthetic polymer. In some embodiments, the water-soluble synthetic polymer is polyvinyl alcohol. In some cases, the polyvinyl alcohol is at least 78% hydrolyzed, e.g., 79-81% hydrolyzed, 87-89% hydrolyzed, 87-90% hydrolyzed, or 99% hydrolyzed. In some embodiments, the polyvinyl alcohol (PVA) is 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% hydrolyzed. In some embodiments, the PVA is 89% hydrolyzed. In some embodiments, the method comprises contacting the population of cells (e.g., NKX6.1-positive pancreatic progenitor cells) with XXI, Alk5i, T3 or GC-1, RA, Santi, and betacellulin, PDBU, and NVP-TNKS656 for a period of 7 days, to induce the differentiation of at least one NKX6.1-positive pancreatic progenitor cell in the population into an insulin-positive endocrine cell, wherein the insulin-positive endocrine cell expresses insulin. In some embodiments, the method comprises contacting the population of cells (e.g., NKX6.1-positive pancreatic progenitor cells) with XXI, Alk5i, T3 or GC-1, RA, Santi, betacellulin, and LDN193189 for a period of 7 days, to induce the differentiation of at least one NKX6.1-positive pancreatic progenitor cell in the population into an insulin-positive endocrine cell, wherein the insulin-positive endocrine cell expresses insulin. In some embodiments, one or more differentiation factors are added in a portion of the Stage 5, for instance, only the first 1, 2, 3, 4, 5, or 6 days of the period of time for Stage 5, or the last 1, 2, 3, 4, 5, or 6 days of the period of time for Stage 5. In one example, the cells are contacted with SHH signaling pathway inhibitor the PKC activator, the retinoic acid, and / or the wnt signaling pathway inhibitor for only the first 2, 3, 4, or 5 days during Stage 5, after which the SHH signaling pathway inhibitor, the PKC activator, the retinoic acid, and / or the wnt signaling pathway inhibitor are not included in or removed from the culture medium. In another example, the cells are contacted with BMP signaling pathway inhibitor for only the first 1, 2, or 3 days during Stage 5, after which the BMP signaling pathway inhibitor is removed from the culture medium. In some embodiments, the method comprises contacting the population of cells (e.g., NKX6.1-positive pancreatic progenitor cells) with one or more metabolites. In some embodiments, the method comprises contacting the population of cells (e.g., NKX6.1-positive pancreatic progenitor cells) with one or more of an acetyl CoA-related metabolite, a vitamin, histone deacetylase inhibitor (HDACi), a redox homeostasis regulator, a one carbon metabolism pathway intermediate, and / or glutamine. Examples of metabolites include glutamine, taurine, acetate, beta-hydroxybutyrate, biotin, and formate. In some embodiments, a composition (e.g., medium) of the disclosure comprises an acetyl CoA-related metabolite. Exemplary acetyl CoA-related metabolites include, but are not limited to acetate, pyruvate, ketogenic amino acids, valine, leucine, isoleucine, phenylalanine, tyrosine, lysine, tryptophan, fatty acids, CoA, Isovaleryl-CoA, and P-hydroxybutyrate. In some embodiments, the acetyl CoA-related metabolite is acetate. In some embodiments, the acetyl CoA-related metabolite is present in or is added to a composition of the disclosure at a concentration of about 10 nM, about 50 nM, about 80 nM, about 100 nM, about 120 nM, about 140 nM, about 150 nM, about 200 nM, about 300 nM, about 500 nM, about 800 nM, about 1 pM, about 10 pM, about 100 pM, about 500 pM, about 800 pM, about 900 pM, about 1 mM, about 2 mM, about 3 mM, about 5 mM, or about 10 mM. In some embodiments, the acetyl CoA-related metabolite is present in or is added to a composition of the disclosure at a concentration of about 0.01-50 mM, 0.1-50 mM, 0.5-50 mM, 0.01-20 mM, 0.1-20 mM, 0.5-20 mM, 0.01-10 mM, 0.1-10 mM, 0.5-10 mM, 0.8-25 mM, 0.8-10 mM, 0.8-5 mM, 0.8-2 mM, 0.81.5 mM, 0.8-1.2 mM, 0.9-1.1 mM, or 0.95-1.05 mM. In some embodiments, the acetyl CoA-related metabolite is acetate present at a concentration of about 1 mM. In some embodiments, the acetyl CoA-related metabolite is acetate present at a concentration of about 50-1000 nM, 50800 nM, 50-500 nM, 50-300 nM, 50-250 nM, 100-200 nM, or 125-175 nM. In some embodiments, the acetyl CoA-related metabolite is acetate present at a concentration of about 160 nM. In some embodiments, a composition (e.g., medium) of the disclosure comprises one or more vitamins. Exemplary vitamins include, but are not limited to biotin, vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B6 (pyridoxine) and vitamin B12 (cyanocobalamin). In some embodiments the vitamin modulates fatty acid synthesis. In some embodiments the vitamin modulates branched-chain amino acid metabolism. In some embodiments the vitamin modulates or participates as a co-factor in the TCA cycle, e.g., as a cofactor for pyruvate carboxylase. In some embodiments, the vitamin is biotin. In some embodiments, the vitamin is present in or is added to a composition of the disclosure at a concentration of about 100 nM, about 300 nM, about 500 nM, about 600 nM, about 700 nM, about 800 nM, about 900 nM, about 1 pM, about 1.5 pM, about 3 pM, about 5 pM, about 10 pM, or about 100 pM. In some embodiments, the vitamin is biotin present at a concentration of about 800 nM. In some embodiments, the vitamin is present in or is added to a composition of the disclosure at a concentration of about 1 nM to 500 pM, 1 nM to 100 pM, 1 nM to 10 pM, 1 nM to 1 pM, 1 nM to 800 nM, 1 nM to 600 nM, 1 nM to 400 nM, 1 nM to 300 nM, 1 nM to 200 nM, 25 nM to 500 pM, 25 nM to 100 pM, 25 nM to 10 pM, 25 nM to 1 pM, 25 nM to 800 nM, 25 nM to 600 nM, 25 nM to 400 nM, 25 nM to 300 nM, 25 nM to 200 nM, 50 nM to 500 pM, 50 nM to 100 pM, 50 nM to 10 pM, 50 nM to 1 pM, 50 nM to 800 nM, 50 nM to 600 nM, 50 nM to 400 nM, 50 nM to 300 nM, 50 nM to 200 nM, 100 nM to 500 pM, 100 nM to 100 pM, 100 nM to 10 pM, 100 nM to 1 pM, 100 nM to 800 nM, 100 nM to 600 nM, 100 nM to 400 nM, 100 nM to 300 nM, or 100 nM to 200 nM. In some embodiments, a composition (e.g., medium) of the disclosure comprises a histone deacetylase inhibitor (HDACi). Exemplary histone deacetylase inhibitors (HDACi) include, but are not limited to P-Hydroxybutyrate, butyric acid, class I HDACi, class IIA HDACi, class IIB HDACi, class III HDACi, class IV HDACi, HDAC-1, HDAC-2, HDAC-3, HD AC-4, HD AC-5, HD AC-6, HD AC-7, HD AC-8, HD AC-9, HD AC-10, HDAC-11, sirtuins, SIRT1, SIRT2, SIRT3, SIRT4, SIRT5, SIRT6, SIRT7, Vorinostat (suberoylanilide hydroxamic acid, SAHA, MK0683), Entinostat (MS-275, SNDX-275), Panobinostat (LBH589, NVP-LBH589), Trichostatin A (TSA), Mocetinostat (MGCD0103, MG0103), GSK3117391 (GSK3117391 A, HDAC-IN-3), BRD33O8, BRD33O8, Tubastatin A TFA (Tubastatin A trifluoroacetate salt), Tubastatin A, SIS 17, NKL 22, BML-210 (CAY10433), TC-H 106, SR-4370, Belinostat (PXD101, NSC726630, PX-105684), Romidepsin (FK228, Depsipeptide, FR 901228, NSC 630176), MC1568, Givinostat (ITF2357), Dacinostat (LAQ824, NVP-LAQ824), CUDC-101, Quisinostat (JNJ-26481585), Pracinostat (SB939), PCI-34051, Droxinostat (NS 41080), Abexinostat (PCI- 24781), Abexinostat (PCI-24781, CRA-024781), RGFP966, AR-42 (HDAC-42), Ricolinostat (ACY-1215, Rocilinostat), Valproic acid sodium salt (Sodium valproate), Tacedinaline (CI994, PD-123654, GOE-5549, Acetyldinaline), Fimepinostat (CUDC-907), Sodium butyrate (NaB), Curcumin, Diferuloylmethane, M344, Tubacin, RG2833 (RGFP109), RG2833 (RGFP109), Resminostat (RAS2410), Divalproex Sodium, Scriptaid (GCK 1026), Sodium Phenylbutyrate, Sinapinic acid (Sinapic acid), TMP269, Santacruzamate A (CAY10683), TMP195 (TFMO 2), Valproic acid (VPA), UF010, Tasquinimod (ABR-215050), SKLB-23bb, Isoguanosine, Sulforaphane, BRD73954, Citarinostat (ACY-241, HDAC-IN-2), Suberohydroxamic acid, Splitomicin, HPOB, LMK-235, Biphenyl-4-sulfonyl chloride (p-Phenylbenzenesulfonyl, 4- Phenylbenzenesulfonyl, p-Biphenylsulfonyl), Nexturastat A, TH34, Tucidinostat (Chidamide, HBI-8000, CS-055), (-)-Parthenolide, WT161, CAY10603, CAY10603, ACY-738, Raddeanin A, Tinostamustine(EDO-SlOl), Domatinostat (4SC-202), and BG45. In some embodiments, the HDACi is P-Hydroxybutyrate. In some embodiments, the HDACi is present in or is added to a composition of the disclosure at a concentration of about 100 nM, about 300 nM, about 500 nM, about 600 nM, about 700 nM, about 800 nM, about 900 nM, about 1 pM, about 1.5 pM, about 3 pM, about 5 pM, about 10 pM, or about 100 pM. In some embodiments, the HDACi is P-Hydroxybutyrate present at a concentration of about 200 nM. In some embodiments, the HDACi is present in or is added to a composition of the disclosure at a concentration of about 1 nM to 500 pM, 1 nM to 100 pM, 1 nM to 10 pM, 1 nM to 1 pM, 1 nM to 800 nM, 1 nM to 600 nM, 1 nM to 400 nM, 1 nM to 300 nM, 1 nM to 200 nM, 25 nM to 500 pM, 25 nM to 100 pM, 25 nM to 10 pM, 25 nM to 1 pM, 25 nM to 800 nM, 25 nM to 600 nM, 25 nM to 400 nM, 25 nM to 300 nM, 25 nM to 200 nM, 50 nM to 500 pM, 50 nM to 100 pM, 50 nM to 10 pM, 50 nM to 1 pM, 50 nM to 800 nM, 50 nM to 600 nM, 50 nM to 400 nM, 50 nM to 300 nM, 50 nM to 200 nM, 100 nM to 500 pM, 100 nM to 100 pM, 100 nM to 10 pM, 100 nM to 1 pM, 100 nM to 800 nM, 100 nM to 600 nM, 100 nM to 400 nM, 100 nM to 300 nM, or 100 nM to 200 nM. In some embodiments, a composition (e.g., medium) of the disclosure comprises a redox homeostasis regulator. Exemplary redox homeostasis regulators include, but are not limited to taurine, respiratory chain regulators, free radical scavengers, regulators of mitochondrial protein synthesis, allium sulphur compounds, anthocyanins, beta-carotene, catechins, copper, cryptoxanthins, flavonoids, indoles, isoflavonoids, lignans, lutein, lycopene, alpha lipoic acid, ellagic acid, manganese, polyphenols, selenium, glutathione, vitamin A, vitamin C, vitamin E, zinc, superoxide disutases, GSHPx, Prx-I, catalase, and co-enzyme Q10. In some embodiments, the redox homeostasis regulator is taurine. In some embodiments, the redox homeostasis regulator is present in or is added to a composition of the disclosure at a concentration of about 100 nM, about 500 nM, 1 pM, about 10 pM, about 20 pM, about 30 pM, about 40 pM, about 50 pM, about 60 pM, about 70 pM, about 80 pM, about 90 pM, about 100 pM, about 110 pM, about 110 pM, about 150 pM, or about 200 pM. In some embodiments, the redox homeostasis regulator is taurine. In some embodiments, the redox homeostasis regulator is taurine present at a concentration of about 90 pM. In some embodiments, the redox homeostasis regulator intermediate is present or is added at a concentration of about 100 nM to 1 mM, 500 nM to 1 mM, 1 pM to 1 mM, 10 pM to 1 mM, 20 pM to 1 mM, 30 pM to 1 mM, 30 pM to 1 mM, 40 pM to 1 mM, 50 pM to 1 mM, 60 pM to 1 mM, 70 pM to 1 mM, 80 pM to 1 mM, 100 nM to 250 pM, 500 nM to 250 pM, 1 pM to 250 pM, 10 pM to 250 pM, 20 pM to 250 pM, 30 pM to 250 pM, 30 pM to 250 pM, 40 pM to 250 pM, 50 pM to 250 pM, 60 pM to 250 pM, 70 pM to 250 pM, 100 nM to 100 pM, 500 nM to 100 pM, 1 pM to 100 pM, 10 pM to 100 pM, 20 pM to 100 pM, 30 pM to 100 pM, 40 pM to 100 pM, 50 pM to 100 pM, 60 pM to 100 pM, 70 pM to 100 pM, or 80 pM to 100 pM. In some embodiments, a composition (e.g., medium) of the disclosure comprises a one carbon metabolism pathway intermediate. Exemplary one carbon metabolism pathway intermediates include, but are not limited to formate, tetrahydrofolate (THF), 10-formylTHF; 5,10-meTHF; 5,10-meTHF; and 10-formylTHF. In some embodiments, the one carbon metabolism pathway intermediate is formate present at a concentration of about 50 pM. In some embodiments, the one carbon metabolism pathway intermediate is present or is added at a concentration of about 100 nM to 1 mM, 500 nM to 1 mM, 1 pM to 1 mM, 10 pM to 1 mM, 20 pM to 1 mM, 30 pM to 1 mM, 100 nM to 250 pM, 500 nM to 250 pM, 1 pM to 250 pM, 10 pM to 250 pM, 20 pM to 250 pM, 30 pM to 250 pM, 100 nM to 100 pM, 500 nM to 100 pM, 1 pM to 100 pM, 10 pM to 100 pM, 20 pM to 100 pM, 30 pM to 100 pM, 100 nM to 60 pM, 500 nM to 60 pM, 1 pM to 60 pM, 10 pM to 60 pM, 20 pM to 60 pM, 30 pM to 60 pM, 40 pM to 60 pM, or 45 pM to 55 pM. In some embodiments, a composition (e.g., medium) of the disclosure comprises glutamine. Thus in some embodiments, compositions and methods of the disclosure utilize glutamine in a form with increased bioavailability, such as a free glutamine form, such as a non-dipeptide form, a non-alanine-glutamine dipeptide form (e.g., a non-alanyl-l-glutamine form), a non-glycine-glutamine dipeptide form (e.g., a non-glycyl-l-glutamine form), a form that in which glutamine is not conjugated to another amino acid or stabilizing moiety, a monomeric form, a free form, or a combination thereof. In some embodiments, glutamine is provided as a protein hydrolysate. In some embodiments, glutamine is present or is added to a composition of the disclosure at a concentration of from 0.5-20 mM, 0.5-10 mM, 0.5-5 mM, 1-5 mM, 2-5 mM, or 1 mM to 10 mM. In some embodiments, glutamine is present or is added to a composition of the disclosure at a concentration of 3.8-4.2 mM. In some embodiments, glutamine is present or is added to a composition of the disclosure at a concentration of 1-10, 1-7, 1-8, 1-6, 1-5, 1-4, 2-10, 2-7, 2-8, 2-6, 2-5, 2-4, 3-10, 3-7, 3-8, 3-6, 3-5, 3-4, 3.5-4.5, 3.8-4.2, or 3.9-4.1 mM. In some embodiments, glutamine is present or is added to a composition of the disclosure at a concentration of about 4 mM. In some embodiments, at least 0.5 mM, 0.6 mM, 0.7 mM, 0.8 mM, 0.9 mM, 1 mM, 1.5 mM, 2 mM, 2.5 mM, 3 mM, 3.5 mM, 4 mM, 4.5 mM, or 5 mM of the glutamine is not in a dipeptide form. In some embodiments, at least 500 pM, at least 750 pM, at least 1 mM, at least 1.5 mM, at least 2 mM, at least 2.5 mM, at least 2.6 mM, at least 2.7 mM, at least 2.8 mM, at least 2.9 mM, at least 3 mM, at least 3.1 mM, at least 3.2 mM, at least 3.3 mM, at least 3.4 mM, at least 3.5 mM, at least 3.6 mM, at least 3.7 mM, at least 3.8 mM, at least 3.9 mM, at least 4 mM, at least 5 mM, at least 5.5 mM, at least 6 mM, at least 6.5 mM, at least 7 mM, at least 7.5 mM, at least 8 mM, at least 8.5 mM, at least 9 mM, at least 9.5 mM, or at least 10 mM of the glutamine is in a free form. In some embodiments, the method comprises culturing the population of cells (e.g., NKX6.1-positive pancreatic progenitor cells) in a medium, to induce the differentiation of at least one NKX6.1-positive pancreatic progenitor cell in the population into an insulin-positive endocrine cell, wherein the insulin-positive endocrine cell expresses insulin. Aspects of the disclosure involve treatment of cell population comprising PDX1-positive, NKX6.1-positive pancreatic progenitor cells with PKC activator and / or wnt signaling pathway inhibitor, which can lead to increase in percentage of pancreatic a cells, increase in percentage of pancreatic 6 cells, increase in percentage of pancreatic P cells, reduction in percentage of EC cells, or any combination thereof, in the cell population of pancreatic endocrine cells generated according to the method disclosed herein. In some embodiments, the method comprises contacting a population of cells comprising PDX1-positive, NKX6.1-positive pancreatic progenitor cells with a first composition comprising a FOXO1 inhibitor, notch signaling inhibitor, a PKC activator, a ROCK inhibitor, a growth factor from TGFP superfamily, a growth factor from FGF family, a RA signaling pathway activator, and a SHH pathway inhibitor, for one to two days, thereby obtaining a first transformation cell population comprising PDX1-positive, NKX6.1-positive pancreatic progenitor cells; and contacting the first transformation cell population comprising PDX1-positive, NKX6.1-positive pancreatic progenitor cells with a second composition comprising the PKC activator, notch signaling inhibitor, a TGF-P signaling pathway inhibitor, a TH signaling pathway activator, BMP pathway inhibitor, ROCK inhibitor, retinoic acid, and EGF-family growth factor, wnt signaling pathway inhibitor, and / or an epigenetic modifying compound, for one to two days, thereby obtaining a second transformation cell population comprising NKX6.1-positive, ISL1-positive endocrine cells. Pancreatic P Cells Aspects of the disclosure involve generating pancreatic P cells (e.g., non-native pancreatic P cells / SC-P cells) and additional methods of generating them. Non-native pancreatic P cells, In some embodiments, resemble endogenous mature P cells in form and function, but nevertheless are distinct from native P cells. In some embodiments, the insulin-positive pancreatic endocrine cells generated using the method provided herein can form a cell cluster, alone or together with other types of cells, e.g., precursors thereof, e.g., stem cell, definitive endoderm cells, primitive gut tube cell, PDX1-positive pancreatic progenitor cells, or NKX6.1-positive pancreatic progenitor cells. In some embodiments, any of the cells or populations of cells disclosed herein are in a cell cluster. In some embodiments, the disclosure provides for a composition comprising one or more cell clusters. In some embodiments, the composition comprises 500-20000, 500-15000, 500-10000, 500-5000, 500-2000, 500-1000, 1000-20000, 1000-15000, 1000-10000, 1000-5000, 1000-2000, 2000-20000, 2000-15000, 2000-10000, 2000-5000, 5000-20000, 5000-15000, 500010000, 10000-20000, 10000-15000, 15000-20000, or 3000-9000 cell clusters. In some aspects, provided herein are cell clusters that resemble the functions and characteristics of endogenous pancreatic islets. Such cell clusters can mimic the function of endogenous pancreatic islets in regulating metabolism, e.g., glucose metabolism in a subject. In some embodiments, a composition or cell population of the present disclosure comprises NKX6.1-positive, ISL-positive cells that express lower levels of MAFA than NKX6.1-positive, ISL-positive cells from the pancreas of a healthy control adult subject. In some embodiments, the composition or cell population comprises NKX6.1-positive, ISL-positive cells that express higher levels of MAFB than NKX6.1-positive, ISL-positive cells from the pancreas of a healthy control adult subject. In some embodiments, the composition or cell population comprises NKX6.1-positive, ISL-positive cells that express higher levels of SIX2, HOPX, IAPP and / or UCN3 than NKX6.1-positive, ISL-positive cells from the pancreas of a healthy control adult subject. In some embodiments, a composition or cell population of the present disclosure comprises NKX6.1-positive, ISL-positive cells that do not express MAFA. In some embodiments, the composition or cell population comprises NKX6.1-positive, ISL-positive cells that express MAFB. In some embodiments, the cell population comprising the insulin-positive endocrine cells can be directly induced to mature into SC-P cells without addition of any exogenous differentiation factors (such as inhibitor of TGF-P signaling pathway, thyroid hormone signaling pathway activator, PKC activator, growth factors from TGF-P superfamily, FGF family, or EGF family, SHH signaling pathway inhibitor, y-secretase inhibitor, ROCK inhibitor, or BMP signaling pathway inhibitor). In some embodiments, the method provided herein comprises contacting a cell population comprising NKX6.1-positive, ISLl-positive endocrine cells with a serum albumin protein, a TGF-P signaling pathway inhibitor, a SHH pathway inhibitor, a TH signaling pathway activator, a protein kinase inhibitor, a ROCK inhibitor, a BMP signaling pathway inhibitor, and / or an epigenetic modifying compound. In some embodiments, the method provided herein comprises contacting a cell population comprising NKX6.1-positive, ISLl-positive endocrine cells with human serum albumin protein. In some embodiments, the method provided herein comprises contacting a cell population comprising NKX6.1-positive, ISLl-positive endocrine cells with a PKC activator. In some embodiments, the cell population comprising the insulin-positive endocrine cells can be induced to mature into SC-P cells by contacting the insulin-positive endocrine cells with differentiation factors. The differentiation factors can comprise at least one inhibitor of TGF-P signaling pathway and thyroid hormone signaling pathway activator as described herein. In some embodiments, SC-P cells can be obtained by contacting a population of cells comprising insulin-positive endocrine cells with Alk5i and T3 or GC-1. In some embodiments, the method provided herein comprises contacting a cell population comprising NKX6.1-positive, ISLl-positive endocrine cells with (i) a TGF-P signaling pathway inhibitor, (ii) a thyroid hormone signaling pathway activator, (iii) an epigenetic modifying compound, (iv) a BMP signaling pathway inhibitor, (v) a ROCK inhibitor, and / or (vi) a protein kinase inhibitor (e.g., staurosporine). In some embodiments, the method provided herein comprises contacting a cell population comprising NKX6.1-positive, ISLl-positive endocrine cells with (i) a growth factor from the FGF family, (ii) a TGF-P signaling pathway inhibitor, (iii) a thyroid hormone signaling pathway activator, (iv) an epigenetic modifying compound, (v) a protein kinase inhibitor, (vi) a ROCK inhibitor, (vii) a BMP signaling pathway inhibitor, and (viii) a lipase inhibitor for about one two five days. In some embodiments, the contacting is for about three days. Any TGF-P signaling pathway inhibitor capable of inducing the differentiation of insulin-positive endocrine cells to mature into SC-P cells (e.g., alone, or in combination with other P cell-differentiation factors, e.g., a thyroid hormone signaling pathway activator) can be used. In some embodiments, the TGF-P signaling pathway comprises TGF-P receptor type I kinase signaling. In some embodiments, the TGF-P signaling pathway inhibitor comprises Alk5 inhibitor II. In some examples, the method comprises contacting insulin-positive endocrine cells with a concentration of a TGF-P signaling pathway inhibitor (e.g., Alk5 inhibitor such as Alk5 inhibitor II), such as, about 0.1 pM, about 0.5 pM, about 1 pM, about 1.5 pM, about 2 pM, about 2.5 pM, about 3 pM, about 3.5 pM, about 4 pM, about 4.5 pM, about 5 pM, about 5.5 pM, about 6 pM, about 6.5 pM, about 7 pM, about 7.5 pM, about 8 pM, about 8.5 pM, about 9 pM, about 9.5 pM, about 10 pM, about 10.5 pM, about 11 pM, about 11.5 pM, about 12 pM, about 12.5 pM, about 13 pM, about 13.5 pM, about 14 pM, about 14.5 pM, about 15 pM, about 15.5 pM, about 16 pM, about 16.5 pM, about 17 pM, about 17.5 pM, about 18 pM, about 18.5pM, about 19 pM, about 19.5 pM, about 20 pM, about 25 pM, about 30 pM, about 35 pM, about 40 pM, about 45 pM, or about 50 pM. In some examples, the method comprises contacting insulin-positive endocrine cells with a concentration of a TGF-P signaling pathway inhibitor (e.g., Alk5 inhibitor such as Alk5 inhibitor II), such as, about 7-13 pM, about 8-12 pM , or about 9-11 pM. In some examples, the method comprises contacting insulin-positive endocrine cells with a concentration of a TGF-P signaling pathway inhibitor (e.g., Alk5 inhibitor such as Alk5 inhibitor II), such as, about 10 pM. Any thyroid hormone signaling pathway activator capable of inducing the differentiation of insulin-positive endocrine cells to mature into SC-P cells (e.g., alone, or in combination with other P cell-differentiation factors, e.g., a TGF-P signaling pathway inhibitor) can be used. In some embodiments, the thyroid hormone signaling pathway activator comprises triiodothyronine (T3). In some embodiments, the thyroid hormone signaling pathway activator comprises GC-1. In some examples, the method comprises contacting insulin-positive endocrine cells with a concentration of thyroid hormone signaling pathway activator (e.g., GC-1), such as, about O.lpM, about 0.12 |aM, about 0.13 |aM, about 0.14 |aM, about 0.15 |aM, about 0.16 |aM, about 0.17 |jM, about 0.18 |aM, about 0.19 |aM, about 0.2 |aM, about 0.21|aM, about 0.22|aM, about 0.23|aM, about 0.24 |aM, about 0.25 |aM, about 0.26 |aM, about 0.27 |aM, about 0.28 |aM, about 0.29 |aM, about 0.3 |aM, about 0.31 |aM, about 0.32 |aM, about 0.33 |aM, about 0.34 |aM, about 0.35 |aM, about 0.4 |aM, about 0.45 |aM, about 0.5 |aM, about 0.6 |aM, about 0.8 |aM, about 1 |jM, about 2 |aM, or about 5 |aM. In some examples, the method comprises contacting insulinpositive endocrine cells with a concentration of thyroid hormone signaling pathway activator (e.g., GC-1), such as, about 0.7-1.3 pM, about 0.8-1.2 pM, or about 0.9-1.1 pM. In some examples, the method comprises contacting insulin-positive endocrine cells with a concentration of thyroid hormone signaling pathway activator (e.g., GC-1), such as, about 1 pM. Any BMP signaling pathway inhibitor capable of inducing the differentiation of insulinpositive endocrine cells to mature into SC-P cells (e.g., alone, or in combination with any of a TGF-P signaling pathway inhibitor and / or a thyroid hormone signaling pathway activator) can be used. In some embodiments, the BMP signaling pathway inhibitor comprises LDN193189 or DMH-1. In some examples, the method comprises contacting insulin-positive endocrine cells with a concentration of BMP signaling pathway inhibitor (e.g., LDN1931189), such as, about 30 nM, about 40 nM, about 50 nM, about 60 nM, about 70 nM, about 80 nM, about 90 nM, about 100 nM, about 110 nM, about 120 nM, about 130 nM, about 140 nM, about 150 nM, about 160 nM, about 170 nM, about 180 nM, about 190 nM, about 200 nM, about 210 nM, about 220 nM, about 230 nM, about 240 nM, about 250 nM, about 280 nM, about 300 nM, about 400 nM, about 500 nM, or about IpM. In some examples, the method comprises contacting insulin-positive endocrine cells with a concentration of BMP signaling pathway inhibitor (e.g., LDN1931189), such as, about 70-130 nM, about 80-120 nM, about 90-110 nM. In some examples, the method comprises contacting NKX6.1-positive pancreatic progenitor cells with a concentration of BMP signaling pathway inhibitor (e.g., LDN1931189), such as, about 100 nM. Any ROCK inhibitor that is capable of inducing the differentiation of insulin-positive endocrine cells to mature into SC-P cells (e.g., alone, or in combination with any of a TGF-P signaling pathway inhibitor and / or a thyroid hormone signaling pathway activator) can be used. In some embodiments, the ROCK inhibitor comprises Thiazovivin, Y-27632, Fasudil / HA1077, or H-l 152. In some embodiments, the ROCK inhibitor comprises Y-27632. In some embodiments, the ROCK inhibitor comprises Thiazovivin. In some examples, the method comprises contacting insulin-positive endocrine cells with a concentration of a ROCK inhibitor (e.g., Y-27632 or Thiazovivin), such as, about 0.2 pM, about 0.5 pM, about 0.75 pM, about 1 pM, about 2 pM, about 3 pM, about 4 pM, about 5 pM, about 6 pM, about 7 pM, about 7.5 pM, about 8 pM, about 9 pM, about 10 pM, about 11 pM, about 12 pM, about 13 pM, about 14 pM, about 15 pM, about 16 |aM, about 17 |aM, about 18 |aM, about 19 |aM, about 20 |aM, about 21 |jM, about 22 |aM, about 23 |aM, about 24 |aM, about 25 |aM, about 26 |aM, about 27 |aM, about 28 |jM, about 29 |aM, about 30 |aM, about 35 |aM, about 40 |aM, about 50 |aM, or about 100 |aM. In some embodiments, the ROCK inhibitor comprises Thiazovivin. In some examples, the method comprises contacting insulin-positive endocrine cells with a concentration of a ROCK inhibitor (e.g., Y-27632 or Thiazovivin), such as, about 2.2-2.8 pM, about 2.3-2.7 pM, or about 2.4-2.6 pM. In some embodiments, the ROCK inhibitor comprises Thiazovivin. In some examples, the method comprises contacting insulin-positive endocrine cells with a concentration of a ROCK inhibitor (e.g., Y-27632 or Thiazovivin), such as, about 2.5 pM. Any epigenetic modifying compound that is capable of inducing the differentiation of insulin-positive endocrine cells to mature into SC-P cells (e.g., alone, or in combination with any of a TGF-P signaling pathway inhibitor and / or a thyroid hormone signaling pathway activator) can be used. In some embodiments, the epigenetic modifying compound comprises a histone methyltransferase inhibitor or a HD AC inhibitor. In some embodiments, the epigenetic modifying compound comprises a histone methyltransferase inhibitor, e.g., DZNep. In some embodiments, the epigenetic modifying compound comprises a HD AC inhibitor, e.g., KD5170. In some examples, the method comprises contacting insulin-positive endocrine cells to mature into SC-P cells with a concentration of an epigenetic modifying compound (e.g., DZNep or KD5170), such as, about 0.01 M, about 0.025 pM, about 0.05 pM, about 0.075 pM, about 0.1 pM, about 0.15 pM, about 0.2 pM, about 0.5 pM, about 0.75 pM, about 1 pM, about 2 pM, about 3 pM, about 4 pM, about 5 pM, about 6 pM, about 7 pM, about 7.5 pM, about 8 pM, about 9 pM, about 10 pM, about 15 pM, about 20 pM, about 25 pM, about 30 pM, about 35 pM, about 40 pM, about 50 pM, or about 100 pM. In some examples, the method comprises contacting insulin-positive endocrine cells to mature into SC-P cells with a concentration of an epigenetic modifying compound (e.g., DZNep or KD5170), such as, about 70-130 nM, about 80120 nM, or about 90-110 nM. In some examples, the method comprises contacting insulinpositive endocrine cells to mature into SC-P cells with a concentration of an epigenetic modifying compound (e.g., DZNep or KD5170), such as, about 100 nM. Any protein kinase inhibitor that is capable of inducing the differentiation insulinpositive endocrine cells to mature into SC-P cells (e.g., alone, or in combination with any of a TGF-P signaling pathway inhibitor and / or a thyroid hormone signaling pathway activator). In some embodiments, the protein kinase inhibitor comprises staurosporine. In some examples, the method comprises contacting insulin-positive endocrine cells with a concentration of a protein kinase inhibitor (e.g., staurosporine), such as, about 0.1 nM, about 0.2 nM, about 0.3 nM, about 0.4 nM, about 0.5 nM, about 0.6 nM, about 0.7 nM, about 0.8 nM, about 0.9 nM, about 1 nM, about 1.1 nM, about 1.2 nM, about 1.3 nM, about 1.4 nM, about 1.5 nM, about 1.6 nM, about 1.7 nM, about 1.8 nM, about 1.9 nM, about 2.0 nM, about 2.1 nM, about 2.2 nM, about 2.3 nM, about 2.4 nM, about 2.5 nM, about 2.6 nM, about 2.7 nM, about 2.8 |aM, about 2.9 nM, about 3 nM, about 3.1 nM, about 3.2 nM, about 3.3 nM, about 3.4 nM, about 3.5 nM, about 3.6 nM, about 3.7 nM, about 3.8 nM, about 3.9 nM, about 4.0 nM, about 4.1 nM, about 4.2 nM, about 4.3 nM, about 4.4 nM, about 4.5 nM, about 4.6 nM, about 4.7 nM, about 4.8 |aM, about 4.9 nM, or about 5 nM. In some examples, the method comprises contacting insulin-positive endocrine cells with a concentration of a protein kinase inhibitor (e.g., staurosporine), such as, about 1-5 nM, about 2-4 nM, or about 2.5-3.5 nM. In some examples, the method comprises contacting insulinpositive endocrine cells with a concentration of a protein kinase inhibitor (e.g., staurosporine), such as, about 3 nM. In some embodiments, the method comprises contacting the population of cells (e.g., NKX6.1-positive, ISLl-positive, insulin-positive cells) with one or more metabolites. In some embodiments, the method comprises contacting the population of cells (e.g., NKX6.1-positive, ISLl-positive, insulin-positive cells) with one or more of an acetyl CoA-related metabolite, a vitamin, histone deacetylase inhibitor (HDACi), a redox homeostasis regulator, a one carbon metabolism pathway intermediate, glutamate, and / or carnitine. Examples of metabolites include taurine, acetate, beta-hydroxybutyrate, biotin, carnitine, glutamate, and formate. In some embodiments, a composition (e.g., medium) of the disclosure comprises an acetyl CoA-related metabolite. Exemplary acetyl CoA-related metabolites include, but are not limited to acetate, pyruvate, ketogenic amino acids, valine, leucine, isoleucine, phenylalanine, tyrosine, lysine, tryptophan, fatty acids, CoA, Isovaleryl-C...

Claims

1. An in vitro composition comprising a population of pancreatic progenitor cells and a medium comprising a Forkhead Box 01 (FoxOl) inhibitor and a notch signaling pathway inhibitor, wherein the population of pancreatic progenitor cells comprises cells that are PDX1-positive and NKX6.1-negative and cells that are PDXl-positive and NKX6.1-positive.

2. The in vitro composition of claim 1, wherein the medium further comprises a PKC activator.

3. The in vitro composition of claim 1 or claim 2, wherein the notch signaling pathway inhibitor is a y-secretase inhibitor.4 The in vitro composition of claim 3, wherein the y-secretase inhibitor is XXI, DAPT or derivatives thereof, optionally wherein the y-secretase inhibitor is XXI.

5. The in vitro composition of any one of claims 1-4, wherein the FOXO1 inhibitor is of formula (LB):or a pharmaceutically acceptable salt, solvate, hydrate, polymorph, co-crystal, tautomer, stereoisomer, isotopically labeled derivative, prodrug, composition, or mixture thereof.

6. The in vitro composition of any one of claims 1-5, wherein the FoxOl inhibitor is present in the medium at a concentration of 0.1-10 pM, optionally wherein the FoxOl inhibitor is present in the medium at a concentration of 1 pM.

7. The in vitro composition of any one of claims 2-6, wherein the PKC activator is phorbol 12,13-dibutyrate (PdBU), TPB, phorbol 12-myristate 13-acetate, bryostatin 1, or derivatives thereof, optionally wherein the PKC activator is PdBU.

8. The in vitro composition of any one of claims 1-7, wherein the medium further comprises one or more agents selected from: a fibroblast growth factor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, and a TGF-P ligand, optionally wherein the medium further comprises a fibroblastgrowth factor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, and a TGF-P ligand.

9. The in vitro composition of any one of claims 1-7, wherein the medium further comprises keratinocyte growth factor (KGF), SANT-1, RA, triazovivin, and activin A.

10. The in vitro composition of any one of claims 1-9, further the medium further comprises a water-soluble synthetic polymer.

11. The in vitro composition of claim 10, wherein the water-soluble synthetic polymer is polyvinyl alcohol, poloxamer, polyvinylpyrrolidone, polyethylene glycol (PEG), PEG copolymers, poly(N-isopropylacrylamide), or polyacrylamide.

12. The in vitro composition of claim 10 or claim 11, wherein the water-soluble synthetic polymer is polyvinyl alcohol (PVA).

13. The in vitro composition of any one of claims 10-12, wherein the water-soluble synthetic polymer has a concentration of 0.005% to 0.5% (w / v), 0.01% to 0.2% (w / v), 0.02% to 0.1% (w / v), or 0.03% to 0.08% (w / v) of the medium.

14. The in vitro composition of claim 12 or claim 13, wherein the PVA is at most 85% hydrolyzed, optionally wherein the PVA is about 80% hydrolyzed.

15. The in vitro composition of any one of claims 1-14, wherein at least 50% of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-negative, and / or no more than 50% of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-positive.

16. The in vitro composition of any one of claims 1-14, wherein no more than 50% of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-negative, and / or at least 50% of the population of pancreatic progenitor cells are PDXl-positive and NKX6.1-positive.

17. The in vitro composition of any one of claims 1-16, wherein medium does not comprise a Wnt inhibitor.

18. An in vitro composition comprising a population of pancreatic progenitor cells comprising cells that are PDXl-positive, NKX6.1-positive, and insulin-negative; and a medium comprising a protein kinase C (PKC) activator and a Wnt signaling pathway inhibitor, wherein the medium does not comprise a FOXO1 inhibitor, and wherein the population of cells had been previously cultured in a medium comprising a FOXO1 inhibitor.

19. The in vitro composition of claim 18, wherein the PKC activator is phorbol 12,13-dibutyrate (PdBU), phorbol 12-myristate 13-acetate, bryostatin 1, or derivatives thereof, optionally wherein the PKC activator is PdBU.

20. The in vitro composition of claim 18 or claim 19, wherein the Wnt signaling pathway inhibitor is a tankyrase inhibitor, optionally wherein the tankyrase inhibitor is NVP-TNKS656.

21. The in vitro composition of any one of claims 18-20, wherein the medium further comprises one or more agents selected from: a sonic hedgehog (SHH) signaling pathway inhibitor, an epidermal growth factor, a notch signaling pathway inhibitor, a TGFP-R1 kinase inhibitor, a thyroid hormone, a bone morphogenetic (BMP) signaling pathway inhibitor, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a histone methyltransferase EZH2 inhibitor, and retinoic acid, optionally wherein the medium further comprises a sonic hedgehog (SHH) signaling pathway inhibitor, an epidermal growth factor, a notch signaling pathway inhibitor, a TGFP-R1 kinase inhibitor, a thyroid hormone, a bone morphogenetic (BMP) signaling pathway inhibitor, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a histone methyltransferase EZH2 inhibitor, and retinoic acid.

22. The in vitro composition of any one of claims 18-20, wherein the medium further comprises SANT-1, betacellulin, XXI, Alk5i, GC-1, LDN-193189, thiazovivin, staurosporine, DZNEP, and retinoic acid.

23. The in vitro composition of any one of claims 18-22, wherein the medium further comprises one or more agents selected from an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, and a one carbon metabolism pathway intermediate, optionally wherein the medium further comprises an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, and a one carbon metabolism pathway intermediate.

24. The in vitro composition of any one of claims 18-22, wherein the medium further comprises acetate, P-hydroxybutyrate, taurine, and formate.

25. The in vitro composition of any one of claims 18-24, wherein the medium further comprises a vitamin, optimally wherein the vitamin is biotin.

26. The in vitro composition of any one of claims 18-25, wherein the medium further comprises glutamine.

27. The in vitro composition of any one of claims 18-26, wherein the medium comprises PDBU, NVP-TNKS656, SANT-1, betacellulin, XXI, Alk5i, GC-1, LDN-193189, thiazovivin,staurosporine, DZNEP, retinoic acid, acetate, P-hydroxybutyrate, taurine, formate, biotin, and glutamine.

28. The in vitro composition of any one of claims 18-27, wherein the medium further comprises a water-soluble synthetic polymer.

29. The in vitro composition of claim 28, wherein the water-soluble synthetic polymer is polyvinyl alcohol, poloxamer, polyvinylpyrrolidone, polyethylene glycol (PEG), PEG copolymers, poly(N-isopropylacrylamide), or polyacrylamide.

30. The in vitro composition of claim 28 or claim 29, wherein the water-soluble synthetic polymer is polyvinyl alcohol (PVA).

31. The in vitro composition of any one of claims 28-30, wherein the water-soluble synthetic polymer has a concentration of 0.005% to 0.5% (w / v), 0.01% to 0.2% (w / v), 0.02% to 0.1% (w / v), or 0.03% to 0.08% (w / v) of the medium.

32. The in vitro composition of claim 30 or claim 31, wherein the PVA is at most 90% hydrolyzed, optionally wherein the PVA is about 87%-89% hydrolyzed.

33. The in vitro composition of any one of claims 18-32, wherein at least 50% of the population of pancreatic progenitor cells are PDX1-positive, NKX6.1-positive, and insulinnegative.

34. The in vitro composition of any one of claims 18-33, further comprising pancreatic endocrine cells that are PDX1-positive, NKX6.1-positive, and insulin-positive.

35. The in vitro composition of any one of claims 18-34, wherein the Wnt signaling pathway inhibitor is present in the medium at a concentration of 0.2 pM-2 pM.

36. The in vitro composition of any one of claims 18-35, wherein the Wnt signaling pathway inhibitor is present in the medium at a concentration of about 2 pM.

37. A method comprising culturing a first population of cells in a first medium, wherein:the first population of cells comprises pancreatic progenitor cells that are PDXl-positive and NKX6.1 negative, and pancreatic progenitor cells that are PDXl-positive and NKX6.1 positive; andthe first medium comprises a Forkhead Box 01 (FoxOl) inhibitor and a notch signaling pathway inhibitor.

38. The method of claim 37, wherein the first medium further comprises a PKC activator.

39. The method of claim 37 or claim 38, wherein the notch signaling pathway inhibitor is a y-secretase inhibitor.

40. The method of claim 39, wherein the y-secretase inhibitor is XXI, DAPT or derivatives thereof, optionally wherein the y-secretase inhibitor is XXI.

41. The method of any one of claims 37-40, wherein the FoxOl inhibitor is of formula (I-B):or a pharmaceutically acceptable salt, solvate, hydrate, polymorph, co-crystal, tautomer, stereoisomer, isotopically labeled derivative, prodrug, composition, or mixture thereof.

42. The method of any one of claims 37-41, wherein the FoxOl inhibitor is present in the first medium at a concentration of 0.1-10 pM, optionally wherein the FoxOl inhibitor is present in the first medium at a concentration of 1 pM.

43. The method of any one of claims 38-42, wherein the PKC activator is phorbol 12,13-dibutyrate (PdBU), TPB, phorbol 12-myristate 13-acetate, bryostatin 1, or derivatives thereof, optionally wherein the PKC activator is PdBU.

44. The method of any one of claims 37-43, wherein the first medium further comprises one or more agents selected from: a fibroblast growth factor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, and a TGF-P ligand, optionally wherein the first medium further comprises a fibroblast growth factor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, and a TGF-P ligand.

45. The method of any one of claims 37-43, wherein the first medium further comprises keratinocyte growth factor (KGF), SANT-1, RA, triazovivin, and activin A.

46. The method of any one of claims 37-45, wherein the first medium does not comprise a Wnt signaling pathway inhibitor.

47. The method of any one of claims 37-46, wherein the first medium further comprises a water soluble synthetic polymer, optionally wherein the water-soluble synthetic polymer is PVA, further optionally wherein the PVA is at most 85% hydrolyzed.

48. The method of any one of claims 37-47, wherein the first population of cells are cultured in the first medium for a period of 24-48 hours, resulting in a second population of cells.

49. The method of claim 48, further comprising culturing the second population of cells with a second medium comprising a Wnt signaling pathway inhibitor and a PKC activator.

50. The method of claim 49, wherein the Wnt signaling pathway inhibitor is a tankyrase inhibitor, optionally wherein the tankyrase inhibitor is NVP-TNKS656.

51. The method of claim 49 or claim 50, wherein the PKC activator is phorbol 12,13-dibutyrate (PdBU), TPB, phorbol 12-myristate 13-acetate, bryostatin 1, or derivatives thereof, optionally wherein the PKC activator is PdBU.

52. The method of any one of claims 49-51, wherein the second medium further comprises one or more agents selected from: an epidermal growth factor, a thyroid hormone, a TGFP-R1 kinase inhibitor, a notch signaling pathway inhibitor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a bone morphogenetic (BMP) signaling pathway inhibitor, and a histone methyltransferase EZH2 inhibitor, optionally wherein the second medium further comprises an epidermal growth factor, a thyroid hormone, a TGFP-R1 kinase inhibitor, a notch signaling pathway inhibitor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a bone morphogenetic (BMP) signaling pathway inhibitor, and a histone methyltransferase EZH2 inhibitor.

53. The method of any one of claims 49-51, wherein the second medium further comprises SANT-1, betacellulin, XXI, Alk5i, GC-1, LDN-193189, thiazovivin, staurosporine, DZNEP, and retinoic acid.

54. The method of any one of claims 49-53, wherein the second medium further comprises one or more agents selected from an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, and a one carbon metabolism pathway intermediate, optionally wherein the second medium further comprises an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, and a one carbon metabolism pathway intermediate.

55. The method of any one of claims 49-53, wherein the second medium further comprises acetate, P-hydroxybutyrate, taurine, and formate.

56. The method of any one of claims 49-55, wherein the second medium further comprises a vitamin, optimally wherein the vitamin is biotin.WO 2023 / 077140                                                 PCT / US2022 / 07901757. The method of any one of claims 49-56, wherein the second medium further comprises glutamine.

58. The method of any one of claims 49-57, wherein the second medium comprises: PDBU, NVP-TNKS656, SANT-1, betacellulin, XXI, Alk5i, GC-1, LDN-193189, thiazovivin, staurosporine, DZNEP, retinoic acid, acetate, P-hydroxybutyrate, taurine, formate, biotin, and glutamine.

59. The method of any one of claims 49-58, wherein the second medium does not comprise a FOXO1 inhibitor.

60. The method of any one of claims 49-59, wherein the second medium further comprises a water-soluble synthetic polymer.

61. The method of claim 60, wherein the water-soluble synthetic polymer is polyvinyl alcohol, poloxamer, polyvinylpyrrolidone, polyethylene glycol (PEG), PEG copolymers, poly(N-isopropylacrylamide), or polyacrylamide.

62. The method of claim 60 or claim 61, wherein the water-soluble synthetic polymer is polyvinyl alcohol (PVA).

63. The method of any one of claims 60-62, wherein the water-soluble synthetic polymer has a concentration of 0.005% to 0.5% (w / v), 0.01% to 0.2% (w / v), 0.02% to 0.1% (w / v), or 0.03% to 0.08% (w / v) of the medium.

64. The method of claim 62 or claim 63, wherein the PVA is at most 90% hydrolyzed, optionally wherein the PVA is about 87%-89% hydrolyzed.

65. The method of any one of claims 49-64, wherein the Wnt signaling pathway inhibitor is present in the second medium at a concentration of 0.2 pM -2 pM.

66. The method of any one of claims 49-65, wherein the Wnt signaling pathway inhibitor is present in the second medium at a concentration of about 2 pM.

67. The method of any one of claims 49-66, wherein the second population of cells are cultured in the second medium for about 24-72 hours, resulting in a third population of cells.

68. The method of claim 67, further comprising culturing the third population of cells in a third medium comprising: a thyroid hormone, a TGFP-R1 kinase inhibitor, a notch signaling pathway inhibitor, a Rho-associated coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a bone morphogenetic (BMP) signaling pathway inhibitor, a histone methyltransferase EZH2 inhibitor, an acetyl CoA related metabolite, an HD AC inhibitor, a redoxhomeostasis regulator, a one carbon metabolism pathway intermediate, a vitamin, glutamine, and a water-soluble synthetic polymer.

69. The method of claim 68, wherein the third medium comprises GC-1, ALK5i II, XXI, triazovivin, staurosporine (SSP), LDN193189, DZNep, acetate, P-hydroxybutyrate, taurine, formate, biotin, glutamine, and PVA, optionally wherein the PVA is at most 90% hydrolyzed.

70. The method of claim 68 or claim 69, wherein the third population of cells are cultured in the third medium for about 48-96 hours, resulting in a fourth population of cells.

71. The method of claim 70, further comprising culturing the fourth population of cells in a fourth medium comprising a TGFP-R1 kinase inhibitor, a thyroid hormone, a bone morphogenetic (BMP) signaling pathway inhibitor, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a histone methyltransferase EZH2 inhibitor, an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, an one carbon metabolism pathway intermediate, a vitamin, glutamine, glutamate, carnitine, albumin, and ZnSO4.

72. The method of claim 70 or claim 71, wherein the fourth medium comprises ALK5i, GC-1, LDN-193189, thiazovivin, staurosporine (SSP), DZBEP, acetate, P-hydroxybutyrate, taurine, formate, biotin, glutamine, glutamate, carnitine, HSA, and ZnSO4.

73. The method of claim 71 or claim 72, wherein the fourth population of cells are cultured in the fourth medium for about 48-96 hours, resulting in a fifth population of cells.

74. The method of claim 73, further comprising culturing the fifth population of cells in a fifth medium comprising glutamine, HSA and ZnSO4, optionally wherein the fifth medium further comprises acetate, P-hydroxybutyrate, taurine, formate, biotin, glutamate, and carnitine.

75. The method of claim 74, wherein the fifth population of cells are cultured in the fifth medium for at least 72 hours, resulting in a sixth population of cells.

76. The method of claim 75, wherein at least 15% of the cells of the sixth population of cells are NKX6.1-negative, IS LI-positive; and wherein less than 12% of the fifth population of cells are NKX6.1-negative, ISLl-negative.

77. A method comprising:(i) culturing a first population of cells in a first medium to obtain a second population of cells, wherein the first population of cells comprises pancreatic progenitor cells that are PDX1-positive and NKX6.1 negative, and pancreatic progenitor cells that are PDXl-positive andWO 2023 / 077140                                                 PCT / US2022 / 079017NKX6.1 positive; and the first medium comprises one or more of: a FoxOl inhibitor, a notch signaling pathway inhibitor, a PKC activator, a fibroblast growth factor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a TGF-P ligand, and a water-soluble synthetic polymer;(ii) culturing the second population of cells obtained in (i) with a second medium to obtain a third population of cells, wherein the second medium comprises one or more of: a Wnt signaling pathway inhibitor, a PKC activator, an epidermal growth factor, a thyroid hormone, a TGFP-R1 kinase inhibitor, a notch signaling pathway inhibitor, a sonic hedgehog (SHH) signaling pathway inhibitor, retinoic acid, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a bone morphogenetic (BMP) signaling pathway inhibitor, a histone methyltransferase EZH2 inhibitor, an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, a one carbon metabolism pathway intermediate, a vitamin, glutamine and a water soluble synthetic polymer (e.g., PVA), and wherein the second medium does not comprise a FOXO1 inhibitor;(iii) culturing the third population of cells obtained in (ii) with a third medium to obtain a fourth population of cells, wherein the third medium comprises one or more of: a notch signaling pathway inhibitor, a TGFP-R1 kinase inhibitor, a thyroid hormone, a bone morphogenetic (BMP) signaling pathway, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, and a histone methyltransferase EZH2 inhibitor, an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, an one carbon metabolism pathway intermediate, a vitamin, glutamine and a water soluble synthetic polymer, and wherein the third medium does not comprise a Wnt signaling pathway inhibitor and a PKC activator;(iv) culturing the fourth population of cells obtained in (iii) with a fourth medium to obtain a fifth population of cells, wherein the fourth medium comprises one or more of: a TGFP-R1 kinase inhibitor, a thyroid hormone, a bone morphogenetic (BMP) signaling pathway inhibitor, a Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitor, a protein kinase inhibitor, a histone methyltransferase EZH2 inhibitor, an acetyl CoA related metabolite, an HD AC inhibitor, a redox homeostasis regulator, an one carbon metabolism pathway intermediate, a vitamin, glutamine, glutamate, carnitine, albumin, and ZnSO4, and wherein the fourth medium does not comprise a Wnt signaling pathway inhibitor and a PKC activator; and(v) culturing the fifth population of cells obtained in (iv) with a fifth medium to obtain a sixth population of cells, wherein the fifth medium comprises one or more of albumin and ZnSO4.

78. The method of any one of claims 37-77, wherein the first population of cells are obtained by differentiation of human embryonic stem cells.

79. A population of in vitro differentiated cells comprising NKX6.1-positive, ISLl-positive cells and NKX6.1-negative, ISLl-positive cells; and ISLl-positive cells; wherein at least 15% of the cells in the population are NKX6.1-negative, ISLl-positive cells; and wherein less than 12% of the cells in the population are NKX6.1-negative, ISLl-negative cells.

80. The population of in vitro differentiated cells of claim 79, comprising at least 60%, at least 70%, at least 75%, at least 80%, about 50-90%, or about 70-85% ISLl-positive cells.

81. The population of in vitro differentiated cells of claim 79 or 80, wherein at least 20% of the ISLl-positive cells are NKX6.1-negative.

82. The population of in vitro differentiated cells of any one of claims 79-81, wherein at least 25%, at least 30%, at least 40%, about 30-50%, or about 40-50% of the ISLl-positive cells are NKX6.1 -negative.

83. The population of in vitro differentiated cells of any one of claims 79-82, comprising up to 20%, up to 30%, up to 40%, up to 50%, or up to 55% of NKX6.1-positive, ISLl-positive cells.

84. The population of in vitro differentiated cells of any one of claims 79-83, comprising less than 25% or less than 20% of NKX6.1-positive, ISLl-negative cells.

85. The population of in vitro differentiated cells of any one of claims 79-84, comprising less than 10% or less than 5% of NKX6.1-negative, ISLl-negative cells.

86. The population of in vitro differentiated cells of any one of claims 79-85, wherein the C-peptide content per 1,000 of the in vitro differentiated cells is at least 300 pM, optionally wherein the C-peptide content per 1,000 of the in vitro differentiated cells is at least 400 pM.

87. The population of in vitro differentiated cells of any one of claims 79-86, wherein the glucagon content per 1,000 of the in vitro differentiated cells is at least 100 pM, optionally wherein the glucagon content per 1,000 of the in vitro differentiated cells is at least 200 pM, at least 300 pM, at least 500 pM, at least 600 pM, at least 700 pM, or at least 800 pM.

88. The population of in vitro differentiated cells of any one of claims 79-87, wherein at least 10% of the in vitro differentiated cells are stem cell-derived alpha cells, optionally wherein at least 20%, at least 25%, at least 30%, at least 35%, about 20-40%, or about 30-40% of the in vitro differentiated cells are stem cell-derived alpha cells.

89. The population of in vitro differentiated cells of any one of claims 79-88, wherein at least 35% of the in vitro differentiated cells are stem cell-derived beta cells, optionally wherein at least 40%, at least 45%, or about 35-50% of the in vitro differentiated cells are stem cell-derived beta cells.

90. The population of in vitro differentiated cells of any one of claims 79-89, wherein at least 5% of the in vitro differentiated cells are stem cell-derived delta cells, optionally wherein about 5-10% of the in vitro differentiated cells are stem cell derived delta cells.

91. The population of in vitro differentiated cells of any one of claims 79-90, wherein at least 5% of the in vitro differentiated cells are glucagon-positive and somatostatin-negative.

92. The population of in vitro differentiated cells of any one of claims 79-91, wherein at least 5% of the in vitro differentiated cells are glucagon-negative and somatostatin-positive.

93. The population of in vitro differentiated cells of any one of claims 79-92, wherein less than 10% of the in vitro differentiated cells are both ISL1-1 negative and NKX6.1-negative.

94. The population of in vitro differentiated cells of any one of claims 79-93, wherein about 5-10% of the in vitro differentiated cells are both ISL1-1 negative and NKX6.1-negative.

95. The population of in vitro differentiated cells of any one of claims 79-94, wherein less than 20% of the in vitro differentiated cells are both ISLl-negative and NKX6.1-positive.

96. The population of in vitro differentiated cells of any one of claims 79-95, wherein about 10-20% of the in vitro differentiated cells are both ISLl-negative and NKX6.1-positive.

97. A population of in vitro differentiated cells comprising NKX6.1-positive, ISLl-positive cells and NKX6.1-negative, ISLl-positive cells; wherein at least 15% of the cells in the population are NKX6.1-positive, ISLl-positive cells; wherein at least 10% of the cells in the population are NKX6.1-negative, ISLl-positive cells; and wherein less than 12% of the cells in the population are NKX6.1-negative, ISLl-negative cells.

98. A population of in vitro differentiated cells comprising NKX6.1-positive, ISLl-positive cells and NKX6.1-negative, ISLl-positive cells; wherein at least 15% of the cells in the population are NKX6.1-positive, ISLl-positive cells; wherein at least 10% of the cells in the population are NKX6.1-negative, ISLl-positive cells; and wherein between 5-25% of the cells in the population are NKX6.1-positive, ISLl-negative cells.

99. The population of in vitro differentiated cells of claim 97 or claim 98, wherein at least 30% of the cells in the population are NKX6.1-positive, ISLl-positive cells.

100. The population of in vitro differentiated cells of claim 99, wherein 30-60% of the cells in the population are NKX6.1-positive, ISLl-positive cells, optionally wherein 35-50% of the cells in the population are NKX6.1-positive, ISLl-positive cells.

101. The population of in vitro differentiated cells of any one of claims 97-100, wherein at least 25% of the cells in the population are NKX6.1-negative, ISLl-positive cells.

102. The population of in vitro differentiated cells of claim 101, wherein 25-50% of the cells in the population are NKX6.1-negative, ISLl-positive cells, optionally wherein 30-45% of the cells in the population are NKX6.1-negative, ISLl-positive cells.

103. The population of in vitro differentiated cells of any one of claims 97-102, wherein 112% of the cells in the population are NKX6.1-negative, ISLl-negative cells, optionally wherein 2-12% of the cells in the population are NKX6.1-negative, ISLl-negative cells.

104. The population of in vitro differentiated cells of any one of claims 97-102, wherein between 5-25% of the cells in the population are NKX6.1-positive, ISLl-negative cells, optionally wherein between 9-25% of the cells in the population are NKX6.1-positive, ISLl-negative cells.

105. The population of in vitro differentiated cells of any one of claims 97-104, wherein there are more NKX6.1-positive, ISLl-positive cells than NKX6.1-negative, ISLl-positive cells in the population.

106. The population of in vitro differentiated cells of any one of claims 79-105, further comprising a medium.

107. The population of in vitro differentiated cells of claim 106, wherein the medium comprises a sugar.

108. The population of in vitro differentiated cells of claim 107, wherein the sugar is sucrose or glucose.

109. The population of in vitro differentiated cells of claim 107 or claim 108, wherein the medium comprises the sugar at a concentration of between about 0.05% and about 1.5%.

110. The population of in vitro differentiated cells of any one of claims 107-109, wherein the medium is a CMRL medium or wherein the medium is HypoThermosol® FRS Preservation Media.

111. The population of in vitro differentiated cells of any one of claims 79-110, wherein the population of cells are in a cell cluster or multiple cell clusters.

112. The population of in vitro differentiated cells of any one of claims 79-111, wherein the cell cluster is between 125-225 microns, 130-160, 170-225, 140-200, 140-170, 160-220, 170215, and 170-200 microns in diameter.

113. The population of in vitro differentiated cells of any one of claims 79-112, wherein the population comprises NKX6.1-positive, ISLl-positive cells that express lower levels of MAFA than NKX6.1-positive, ISLl-positive cells from the pancreas of a healthy control adult subject.

114. The population of in vitro differentiated cells of any one of claims 79-113, wherein the population comprises NKX6.1-positive, ISLl-positive cells that express higher levels of MAFB than NKX6.1-positive, ISLl-positive cells from the pancreas of a healthy control adult subject.

115. The population of in vitro differentiated cells of any one of claims 79-114, wherein the population comprises NKX6.1-positive, ISLl-positive cells that express higher levels of SIX2, HOPX, IAPP and / or UCN3 than NKX6.1-positive, ISLl-positive cells from the pancreas of a healthy control adult subject.

116. The population of in vitro differentiated cells of any one of claims 79-115, wherein the population comprises NKX6.1-positive, ISLl-positive cells that do not express MAFA.

117. The population of in vitro differentiated cells of any one of claims 79-116, wherein the population comprises NKX6.1-positive, ISLl-positive cells that express MAFB.

118. The population of in vitro differentiated cells of any one of claims 79-117, wherein the population of cells is derived from stem cells in vitro.

119. The population of in vitro differentiated cells of any one of claims 79-118, wherein the stem cells are genetically modified.

120. The population of in vitro differentiated cells of claim 119, wherein the stem cells have reduced expression of one or more of beta-2 microglobulin, CIITA, HLA-A, HLA-B, HLA-C, HLA-DP, HLA-DQ, and HLADR, relative to stem cells that are not genetically modified.

121. The population of in vitro differentiated cells of claim 119 or claim 120, wherein the stem cells have increased expression of CD47, PDL1, HLA-G, CD46, CD55, CD59 and CTLA, relative to stem cells that are not genetically modified.

122. The population of in vitro differentiated cells of any one of claims 118-121, wherein the pluripotent stem cells are ABO blood group type O or have been genetically modified such that the cell is ABO blood group type O.

123. An in vitro composition comprising the population of in vitro differentiated cells of any one of claims 79-122 and a medium.

124. The in vitro composition of claim 123, wherein the medium comprises human serum albumin.

125. The in vitro composition of claim 123 or 124, wherein the medium comprises glutamine.

126. The in vitro compositions of any one of claims 123-125, wherein the medium comprises any one or more of the following: an inorganic compound, an Alk5 inhibitor, a thyroid hormone receptor beta-specific agonist, a BMP type I receptor inhibitor, a RHO / ROCK pathway inhibitor, a protein kinase inhibitor, or a S-adenosylhomocysteine hydrolase inhibitor.

127. The in vitro composition of any one of claims 123-126, wherein the medium comprises any one or more of the following: ZnSO4, Alk5i, GC-1, LDN-193189, thiazovivin, staurosporine, or DZNEP.

128. The in vitro composition of any one of claims 123-127, wherein the medium comprises any one or more of L-glutamate, L-carnitine, taurine, acetate, beta-hydroxybutarate, biotin or formate.

129. An implantable encapsulation device including an internal volume comprising the composition of any one of claims 79-122 disposed therein.

130. The implantable encapsulation device of claim 129, comprising at least one membrane that at least partially defines the internal volume.

131. The implantable encapsulation device of claim 130, wherein the at least one membrane includes a first membrane and a second membrane, wherein the first membrane and the second membrane are bonded together to form a seal extending at least partially around the internal volume disposed between the first membrane and the second membrane.

132. The implantable encapsulation device of claim 130 or claim 131, wherein the at least one membrane comprises at least one selected from PVDF, PTFE, ePTFE, PCL, PE / PES, PP, PS, PMMA, PLGA, and PLLA.

133. The implantable encapsulation device of any one of claims 130-132, wherein the at least one membrane comprises ePTFE.

134. The implantable encapsulation device of any one of claims 130-133, wherein the device has been implanted in a subject having diabetes.WO 2023 / 077140                                                 PCT / US2022 / 079017135. The implantable encapsulation device of claim 134, wherein the subject has Type I Diabetes.

136. A method of treating a subject, the method comprising administering to the subject a composition comprising the population of in vitro differentiated cells of any one of claims 795    122.

137. A method of treating a subject, the method comprising administering to the subject a composition comprising a population in vitro differentiated cells comprising NKX6.1-positive, ISLl-positive cells and NKX6.1-negative, ISLl-positive cells; wherein the population comprises more NKX6.1-positive, ISLl-positive cells than NKX6.1-negative, ISLl-positive cells; wherein10 at least 15% of the cells in the population are NKX6.1-negative, ISLl-positive cells; and wherein less than 12% of the cells in the population are NKX6.1-negative, ISLl-negative cells.

138. A method of treating a subject, the method comprising implanting into the subject a implantable encapsulation device comprising a population in vitro differentiated cells comprising NKX6.1-positive, ISLl-positive cells and NKX6.1-negative, ISLl-positive cells; wherein the15 population comprises more NKX6.1-positive, ISLl-positive cells than NKX6.1-negative, ISLl-positive cells; wherein at least 15% of the cells in the population are NKX6.1-negative, ISLl-positive cells; and wherein less than 12% of the cells in the population are NKX6.1-negative, ISLl-negative cells.

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